Firewall relay info
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09-08-2006 | 04:09 AM
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Firewall relay info
ORIGINAL: silvercoupe97
*edited*
Those 30 amp relays can be had at Radio Shack. The factory replacements can be upwards of ~$90. So, I would recommend going to Radio Shack. I would also get a Haynes or Chiltons manual if you don't already have one.
*edited*
yes the 30 amp bosch style relays will work just fine to replace any of the relays (ASD, fuel pump, transmission etc)
The relays are located on the firewall near the brake master cylinder, on the driver's side. There are 2-4 relays there depending on the year and options of your car.
The relays are located on the firewall near the brake master cylinder, on the driver's side. There are 2-4 relays there depending on the year and options of your car.
Now you may not have the transmission relay (only on auto's) and you may have another one to the right of the transmission relay
however the fuel pump relay is always on the left and the ASD is always beside it
hope that helps
however the fuel pump relay is always on the left and the ASD is always beside it
hope that helps
Tech Tips
By Dave Sill
Some Tips for Diagnosing Chrysler's EATX System
“Electronically controlled transaxle systems are capable of learning the customer's driving habits. A customer with a heavy foot will cause the TCM to learn to shift late and hard. On the other side, the TCM will learn to shift early and soft for someone with a light foot.”
In 1989, Chrysler decided to throw a little fun into their transmissions by the fully electronic controlled transaxle. This system is still used today on most of Chrysler's front-wheel drive vehicles. The electronically controlled transaxle (EATX) system consists of a transaxle control module, a solenoid pack, several sensors and switches and finally, the serial bus.
The transaxle control module (TCM) is programmed to monitor more than sensors. It gathers information from the bus and combines it with TCM sensors and switches for shift points and diagnosis.
Electronically controlled transaxle systems are capable of learning the customer's driving habits. A customer with a heavy foot will cause the TCM to learn to shift late and hard. On the other side, the TCM will learn to shift early and soft for someone with a light foot.
The EATX system also watches for a request for vehicle speed control and when it sees a request, it adds "grade hunting." This alters the shifting patterns to help prevent excessive shifting and variations in vehicle speed on those hilly roads.
When diagnosing a Chrysler electronically controlled transaxle, make sure any recent fluid flushes or changes were filled with the correct fluid type. ATF+4 is compatible with all transaxles except on 1999 and earlier minivans, which can have TCC chatter. So continue to use ATF+3 on them (per Service Bulletin No. 21-006-01). Check for codes or lack of codes in the transmission, body controller and powertrain. It's also a good idea to record the clutch volume index (CVI) even if you feel there is not an internal problem. When you erase the TCM's codes, you also erase the CVIs stored in the TCM. If the situation arises where you need to look at CVIs, remember that if you erase them, they will not be there.
Clutch volume index is the transaxle controller's way of monitoring the efficiency of the clutch packs. Every time the vehicle is driven, the TCM measures how long it takes each clutch pack to completely fill up and stop slipping. Worn friction material or leaking clutch pack seals increase the time it takes for a clutch pack to fill and be able to grab. In this situation, CVIs will appear on the scanner with high numbers for one or more of the clutches. Numbers that are too low might indicate insufficient clearance inside the clutch pack, which would cause it to grab too quickly or possibly never fully release.
Next, check the park/neutral information. On vehicles equipped with a transaxle range sensor, make sure they are reading correctly all the time. If you have an intermittent limp-in operation with a pressure switch fault, it could be caused by incorrect input to the TCM. The controller is constantly monitoring this input and if it thinks the gear selector has been moved to another gear, it expects to see a change in one or more of the pressure switches. If it doesn't, a code will be stored and you might end up in limp-in. When the transaxle is placed in limp-in on these vehicles, you will only be able to get two gears: second and reverse.
As I mentioned, fluid quality is very important in these transaxles. In many instances, I've seen a number of problems caused by a fluid change with incorrect fluid. And most often, it causes torque convertor clutch problems.
If you get a vehicle in with a complaint of surging or bucking while at a steady speed above 40 mph but no problems when accelerating or decelerating, test drive to determine if it is related to the torque convertor. If it is, ask the customer if they have recently had the transmission serviced or flushed.
On the older EATX systems, the TCM doesn't have great on-board diagnostics. The problem is that the controller doesn't set a code, so therefore you won't have any direction to go in your diagnosis. First, do a visual check of the TCM for heat sink fins. If there aren't any, then it's the old style and should be replaced - not just for diagnostic purposes but for shift quality and longevity. Also check the Safety Shutdown relay and its circuits. When the TCM energizes the relay, it expects to see an output from it but if it doesn't it is supposed to set a DTC. The older controllers tend not to set any codes when it is intermittent.
If you've covered all the basics - fluid, fluid quality, codes and CVIs - then the next step is to start checking electrical circuits. Just give us a call if you need a hand diagnosing any Chrysler system!
Todd Plourde is an IDENTIFIX DaimlerChrysler specialist with 11 years of diagnostic repair experience.
Experience IdentifixThis information is provided by IDENTIFIX®. IDENTIFIX® resources cut diagnostic time and provide repair solutions that increase the shop's bottom line. From Repair-Trac pattern failure quick fixes, to Diagram-Online wiring diagrams by fax, to the Repair Hotline staffed by 32 master techs who specialize in diagnosing complex problems by phone or fax, IDENTIFIX® helps techicians fix more cars in less time.
For more information on IDENTIFIX, call (800) 894-7221, 8 a.m. - 6 p.m. Central Time.
www.identifix.com.
© 2003 IDENTIFIX. All Rights Reserved.
Rate This Article:
Comments?
ASA Main Page || AutoInc. Main Page || ASA Testifies Before SBA Regulatory Fairness Board || Today's Trends in Technical Training || VINs: How They Affect Your Shop || The Importance of a Customer Mailing List || ASA Debuts 'Members Only' Portal || Guest Editorial || Tech to Tech || Tech Tips || News Briefs || Taking the Hill || Around ASA || Net Worth || Stat Corner || Shop Profile || Members' Advantage || Chairman's Message
AutoInc. Magazine ® Vol. LI, April 2003 E-mail: info@autoinc.org, Web Site: http://www.autoinc.org
Copyright © 2003 Automotive Service Association (ASA). All rights reserved.
By Dave Sill
Some Tips for Diagnosing Chrysler's EATX System
“Electronically controlled transaxle systems are capable of learning the customer's driving habits. A customer with a heavy foot will cause the TCM to learn to shift late and hard. On the other side, the TCM will learn to shift early and soft for someone with a light foot.”
In 1989, Chrysler decided to throw a little fun into their transmissions by the fully electronic controlled transaxle. This system is still used today on most of Chrysler's front-wheel drive vehicles. The electronically controlled transaxle (EATX) system consists of a transaxle control module, a solenoid pack, several sensors and switches and finally, the serial bus.
The transaxle control module (TCM) is programmed to monitor more than sensors. It gathers information from the bus and combines it with TCM sensors and switches for shift points and diagnosis.
Electronically controlled transaxle systems are capable of learning the customer's driving habits. A customer with a heavy foot will cause the TCM to learn to shift late and hard. On the other side, the TCM will learn to shift early and soft for someone with a light foot.
The EATX system also watches for a request for vehicle speed control and when it sees a request, it adds "grade hunting." This alters the shifting patterns to help prevent excessive shifting and variations in vehicle speed on those hilly roads.
When diagnosing a Chrysler electronically controlled transaxle, make sure any recent fluid flushes or changes were filled with the correct fluid type. ATF+4 is compatible with all transaxles except on 1999 and earlier minivans, which can have TCC chatter. So continue to use ATF+3 on them (per Service Bulletin No. 21-006-01). Check for codes or lack of codes in the transmission, body controller and powertrain. It's also a good idea to record the clutch volume index (CVI) even if you feel there is not an internal problem. When you erase the TCM's codes, you also erase the CVIs stored in the TCM. If the situation arises where you need to look at CVIs, remember that if you erase them, they will not be there.
Clutch volume index is the transaxle controller's way of monitoring the efficiency of the clutch packs. Every time the vehicle is driven, the TCM measures how long it takes each clutch pack to completely fill up and stop slipping. Worn friction material or leaking clutch pack seals increase the time it takes for a clutch pack to fill and be able to grab. In this situation, CVIs will appear on the scanner with high numbers for one or more of the clutches. Numbers that are too low might indicate insufficient clearance inside the clutch pack, which would cause it to grab too quickly or possibly never fully release.
Next, check the park/neutral information. On vehicles equipped with a transaxle range sensor, make sure they are reading correctly all the time. If you have an intermittent limp-in operation with a pressure switch fault, it could be caused by incorrect input to the TCM. The controller is constantly monitoring this input and if it thinks the gear selector has been moved to another gear, it expects to see a change in one or more of the pressure switches. If it doesn't, a code will be stored and you might end up in limp-in. When the transaxle is placed in limp-in on these vehicles, you will only be able to get two gears: second and reverse.
As I mentioned, fluid quality is very important in these transaxles. In many instances, I've seen a number of problems caused by a fluid change with incorrect fluid. And most often, it causes torque convertor clutch problems.
If you get a vehicle in with a complaint of surging or bucking while at a steady speed above 40 mph but no problems when accelerating or decelerating, test drive to determine if it is related to the torque convertor. If it is, ask the customer if they have recently had the transmission serviced or flushed.
On the older EATX systems, the TCM doesn't have great on-board diagnostics. The problem is that the controller doesn't set a code, so therefore you won't have any direction to go in your diagnosis. First, do a visual check of the TCM for heat sink fins. If there aren't any, then it's the old style and should be replaced - not just for diagnostic purposes but for shift quality and longevity. Also check the Safety Shutdown relay and its circuits. When the TCM energizes the relay, it expects to see an output from it but if it doesn't it is supposed to set a DTC. The older controllers tend not to set any codes when it is intermittent.
If you've covered all the basics - fluid, fluid quality, codes and CVIs - then the next step is to start checking electrical circuits. Just give us a call if you need a hand diagnosing any Chrysler system!
Todd Plourde is an IDENTIFIX DaimlerChrysler specialist with 11 years of diagnostic repair experience.
Experience IdentifixThis information is provided by IDENTIFIX®. IDENTIFIX® resources cut diagnostic time and provide repair solutions that increase the shop's bottom line. From Repair-Trac pattern failure quick fixes, to Diagram-Online wiring diagrams by fax, to the Repair Hotline staffed by 32 master techs who specialize in diagnosing complex problems by phone or fax, IDENTIFIX® helps techicians fix more cars in less time.
For more information on IDENTIFIX, call (800) 894-7221, 8 a.m. - 6 p.m. Central Time.
www.identifix.com.
© 2003 IDENTIFIX. All Rights Reserved.
Rate This Article:
Comments?
ASA Main Page || AutoInc. Main Page || ASA Testifies Before SBA Regulatory Fairness Board || Today's Trends in Technical Training || VINs: How They Affect Your Shop || The Importance of a Customer Mailing List || ASA Debuts 'Members Only' Portal || Guest Editorial || Tech to Tech || Tech Tips || News Briefs || Taking the Hill || Around ASA || Net Worth || Stat Corner || Shop Profile || Members' Advantage || Chairman's Message
AutoInc. Magazine ® Vol. LI, April 2003 E-mail: info@autoinc.org, Web Site: http://www.autoinc.org
Copyright © 2003 Automotive Service Association (ASA). All rights reserved.
Automatic Shut Down (ASD) Relay
Description
The logic module uses this relay to control power going to the fuel pump, ignition coil, fuel injectors, and portions of the power module. For 1985 - 1987 models, the relay was internal to the power module. The 1984 power module, the SMEC, and the SBEC use an external relay. The ASD relay will be activated when the logic module detects a signal from the ignition reference sensor. If the signal is lost while the engine is running or the turbo boost pressure reaches the overboost cut-off point, the ASD relay is shut off and the engine will shut down.
Fault Codes
When the logic module is turning on or off the relay, it momentarily checks the output of the relay/solenoid driver to see if it is responding the way it should. If it does not see about 0V when on (open circuit) or 12V when off (short circuit), a fault code 42 is stored. For later models that use the SMEC or SBEC, the module will monitor the output of the relay to the fuel pump and fuel injectors. If 12V is not detected when the relay is activated, a fault code 42 is stored.
Description
The logic module uses this relay to control power going to the fuel pump, ignition coil, fuel injectors, and portions of the power module. For 1985 - 1987 models, the relay was internal to the power module. The 1984 power module, the SMEC, and the SBEC use an external relay. The ASD relay will be activated when the logic module detects a signal from the ignition reference sensor. If the signal is lost while the engine is running or the turbo boost pressure reaches the overboost cut-off point, the ASD relay is shut off and the engine will shut down.
Fault Codes
When the logic module is turning on or off the relay, it momentarily checks the output of the relay/solenoid driver to see if it is responding the way it should. If it does not see about 0V when on (open circuit) or 12V when off (short circuit), a fault code 42 is stored. For later models that use the SMEC or SBEC, the module will monitor the output of the relay to the fuel pump and fuel injectors. If 12V is not detected when the relay is activated, a fault code 42 is stored.
Here's a pic of from Exile Racing of the relays.
[IMG]local://upfiles/17025/605EA97FF70C42378D4E05163CAF79EB.jpg[/IMG]
[IMG]local://upfiles/17025/5304D40B96B244DB95DB9622DA084ED5.jpg[/IMG]
Bad ASD Relay Symptoms
Usually starts by stalling while driving, progresses into not starting at all, often it will start after several attempts. Engine will have no spark, and you will not hear the fuel pump run when the key is turned on, therefore, no fuel pressure.
These same symptoms have been noticed if a Fuel Pump Relay goes bad or during a computer failure. The Fuel pump relay should not cause a loss of spark.
What to check
First of allwhen you first turn the car on does the Check engine light for a couple seconds? It should as part of the self test when you turn the key on. If it does not then i may be a defective computer, or a burnt out bulb, if the bulb is burnt then you may have a code that you don't even know about. So check that out first.
If your car is a 95-97 perform the key dance. See link for instructions
http://www.2gnt.com/www/files/pcmcode.htm
If you have a 98+ you will need to go someplace such as Autozone, and have them do a free code check. A relay problem usually will not show a code, but if you get a code there is a good chance whatever the code is indicating is causeing your problem.
After the car has sat for a couple minutes with the key off, Turn the key to the ON position, but not far enough to engage the starter. Under normal conditions you will hear the fuel pump run for 2 seconds, to build pressure in the system. The fuel pump is located under the back seat and should be audible from inside the car, or get a friend to stand beside the rear of the car and listen for it.
Check for spark, pull one of the spark pug wire of a plug and insert the metal end of a screwdriver into the end of the wire. Lay the wire and screwdriver onto the metal part of the engine and have someone crank the engine. (don’t touch the screwdriver while the engine is cranking or you’ll be screaming obscenities)
If you see spark and hear the fuel pump than your ASD and Fuel Pump Relays are both good. If you see spark and have no fuel pump noise then i could be the fuel pump relay (or the pump). If the car is experiencing intermittent periods of not starting, then you will need to try this several times. It is possible that the one time you perform these checks, could be the one time the car will start without trouble.
Solutions
The ASD relay is mounted under the hood on the driver’s side of the firewall. near the brake fluid master cylinder
Some cars will have 2, 3, or 4 relays in this position, depending on which transmission you have. The Fuel pump Relay is always on the left (passenger’s side) with the ASD relay beside it. Only Automatic trans cars have the EATX relay, and 95 models have a fourth relay of unknown function.
To replace the relays you have 2 options.
1. Go to the dealer and order a new one. I believe someone payed $20+ at the dealer.
2. Go to your local autoparts store or Radio Shack and buy a 30 amp Bosch style relay. This relay will plug right into your harness and is identical to the original expect it will not clip to the mounting bracket like the original. You can usually disassemble your original and new relays and reassemble the new relay “guts” into the original factory housing. This way it will mount to the bracket.
If this does not solve the problem you could be having computer problems, there are several outputs you can check on the computer, before pricing and looking for a new one, so if you are still having difficulties post again
#2
12-07-2009 | 09:48 PM
Section Moderator
Joined: Mar 2007
Posts: 4,204
Likes: 1
From: Ohio
this is actually a pretty easy circuit to deal with, and ill first explain to you how it works then tell you what you should look for...
a constant 12v is provided to the asd and fuel pump relay along with the pcm.
the pcm then has a KEY ON power circuit. when you turn the key on, the pcm now activates all KEY ON circuits (fuel pump is one of them). the pcm does this via a ground signal.
so the asd relay has 4 pins. 12v power constant, 12v power feed, ground, and 12v power KEY ON. the relay always has power via battery/fuse box, then gets power via another fuse when the key is turned on, then gets GROUND from PCM when key is turned on, then has a pin to deliver power to associated relay circuits.
once the relay receives a ground signal from the pcm, it triggers the relay and activates SEVERAL sources via a junction connector under the PCM. it sends power to the fuel pump relay, coil, alternator, crank position sensor, oxygen sensors and a few others.
the fuel pump relay in your case is next in line. it has a fused 12v constant source via battery/fuse box. 12v Key ON power via ASD relay (this is a power activated relay, where as the ads is ground activated), a aconstant ground, then a signal or power output pin (which goes to the fuel pump). At this point once the fuel pump relay gets its power signal from the asd relay it powers up the fuel pump for a time delay of only 3 seconds. the fuel pump gets its own ground fyi via another circuit. after 3 seconds you will not be able to check for power at any of teh ASD powered sources UNTIL you begin cranking or the motor is running.
now you know how the system works, grab a power source, and apply direct power to pumps power pin. if the pump primes and runs you have a good pump w no power source.
this time take fuel pump connector in hand, and a dvom, have someone turn the key on for u while you check for power at the connector to the pump. if you have power then the pump isnt ur issue... if you dont have power, move along to the fuel pump relay. check for power at the power pin from asd relay when you have a buddy turn the key on... remember you only have roughly 3 seconds to cheeck for power b4 the time delay which is set into the pcm turns off. and just keep following the circuit back until you find the problem/
Battery power to ASD relay, fused ignition power to ASD relay, harness ground to main ground.....
Out of ASD relay to main JC1, From main JC1 to distributer, oxygen sensors, fuel injectors, Fuel pump relay, pcm....
Now onto your problem... Intermittent fuel pump operation.
If you have spark... you can rule out a bad ASD relay... ALL black wires with a red stripe are POWER wires FROM ASD relay.. SO take your test light and while cranking check to see if you have power at distributer or fuel injectors etc, just key on you willonly have power for 5-10 seconds as a prime mechinisim.
moving on. NOT A BAD ASD RELAY. next step... black with red stripe is cycle power to fuel pump relay, then you have constant power from a fuse to fuel pump relay, and same ground as ASD relay... so you can rule out the fuel pump relay ground since you have an operational ASD relay... next step would be check fuel pump fuse, if its goods, back probe pin to fused power in fuel pump relay, if you have power, then crank, do you have power at black wire red stripe from asd relay, if yes then you check power OUT of fuel pump relay, if no power then bad relay.... if no power at black wire red stripe while cranking then broke wire from JC1 to fuel pump relay.
IF you have power out of fuel pump relay then you have either a broken wire from fuel pump relay to fuel pump or bad fuel pump ground which is right there by the back seat.
a constant 12v is provided to the asd and fuel pump relay along with the pcm.
the pcm then has a KEY ON power circuit. when you turn the key on, the pcm now activates all KEY ON circuits (fuel pump is one of them). the pcm does this via a ground signal.
so the asd relay has 4 pins. 12v power constant, 12v power feed, ground, and 12v power KEY ON. the relay always has power via battery/fuse box, then gets power via another fuse when the key is turned on, then gets GROUND from PCM when key is turned on, then has a pin to deliver power to associated relay circuits.
once the relay receives a ground signal from the pcm, it triggers the relay and activates SEVERAL sources via a junction connector under the PCM. it sends power to the fuel pump relay, coil, alternator, crank position sensor, oxygen sensors and a few others.
the fuel pump relay in your case is next in line. it has a fused 12v constant source via battery/fuse box. 12v Key ON power via ASD relay (this is a power activated relay, where as the ads is ground activated), a aconstant ground, then a signal or power output pin (which goes to the fuel pump). At this point once the fuel pump relay gets its power signal from the asd relay it powers up the fuel pump for a time delay of only 3 seconds. the fuel pump gets its own ground fyi via another circuit. after 3 seconds you will not be able to check for power at any of teh ASD powered sources UNTIL you begin cranking or the motor is running.
now you know how the system works, grab a power source, and apply direct power to pumps power pin. if the pump primes and runs you have a good pump w no power source.
this time take fuel pump connector in hand, and a dvom, have someone turn the key on for u while you check for power at the connector to the pump. if you have power then the pump isnt ur issue... if you dont have power, move along to the fuel pump relay. check for power at the power pin from asd relay when you have a buddy turn the key on... remember you only have roughly 3 seconds to cheeck for power b4 the time delay which is set into the pcm turns off. and just keep following the circuit back until you find the problem/
Battery power to ASD relay, fused ignition power to ASD relay, harness ground to main ground.....
Out of ASD relay to main JC1, From main JC1 to distributer, oxygen sensors, fuel injectors, Fuel pump relay, pcm....
Now onto your problem... Intermittent fuel pump operation.
If you have spark... you can rule out a bad ASD relay... ALL black wires with a red stripe are POWER wires FROM ASD relay.. SO take your test light and while cranking check to see if you have power at distributer or fuel injectors etc, just key on you willonly have power for 5-10 seconds as a prime mechinisim.
moving on. NOT A BAD ASD RELAY. next step... black with red stripe is cycle power to fuel pump relay, then you have constant power from a fuse to fuel pump relay, and same ground as ASD relay... so you can rule out the fuel pump relay ground since you have an operational ASD relay... next step would be check fuel pump fuse, if its goods, back probe pin to fused power in fuel pump relay, if you have power, then crank, do you have power at black wire red stripe from asd relay, if yes then you check power OUT of fuel pump relay, if no power then bad relay.... if no power at black wire red stripe while cranking then broke wire from JC1 to fuel pump relay.
IF you have power out of fuel pump relay then you have either a broken wire from fuel pump relay to fuel pump or bad fuel pump ground which is right there by the back seat.
