2002 Dodge Grand Caravan 3.3 Gas, 120K miles

Caravan dies while on vacation. After days of parking-lot trouble shooting lack of power, rough idle & code P0205...ripped apart the top of engine to replace injectors and fortunately tested the wires to #5 injector...finally determined #5 Fuel injector CIRCUIT failed on orig PCM (no pulse through wire, def burned smell in PCM & melted jell spot inside near the edge case). Installed a PCM from junkyard with exact same #'s and put back together the top of the engine ...van started right up and ran great. I drove the van about 400 miles home, then suddenly and without any other warnings, I have a no-start condition the next day.

The ONLY thing that was done just prior to the no-start condition was stopping at auto store, removing & reinstalling a molded rubber tube in the top front of the engine that had hardened & deteriorated (goes from the what appears to be a valve cover to the air filter case...maybe to recover fumes or preheat the intake air???). Sadly, they didn't have one, said it was special heat-tolerant rubber, dealer-only item. I just cut off about 2 inches of the badly deteriorated part (part nearest the engine), reinstalled it and drove home to hunt for one on the web. But then the van wouldn't restart about an hour later.

At first there was no cranking when I turned the key...the dash & radio lights just dimmed....like the starter solenoid was bad. After a few hours of fiddling with it (inspecting starter, fuses, relays, connectors, etc), I noticed that I could mess around with the brake pedal while holding the key in start position and get it to crank for a second or two (sometimes almost cyclically...like pulses...if I held the pedal in just the right position). Now it cranks without touching the brake pedal, but still no start.

- There is no security (always just had a generic, slim key copy).

- There is no spark from the ign pack, but prelim tests possible without removing it from engine were good (frustratingly, the connector is in the back, so its not easy testing on the connector contacts). I don't have a tester to see the pulses on the wires (would an LED work?)

- Checked connectors on sensors I could reach were tight (even removed the ones I could to see it there was any discoloration or corrosion, then reconnected them).

- Tested the ASD & Fuel Pump relay OK, The ASD & Fuel relay both energize when the key is turned on & I hear the fuel pump , but there IS a click somewhere in the panel just about 2 seconds later.

- I've done some prelim. testing on the switch (its still exposed), but stopped investigating it when the cranking did start without messing with the brake pedal & the ASD & fuel pump relays seemed to be energizing.

- Removed the two big PCM harness connectors from side, inspected for discoloration, sprayed with contact spray & reconnected.

- I tried putting orig computer back in and still have the same no start condition (but one code was different).

It IS kind-of like some security has kicked in to disable the van.

So....here are the codes:

Replacement PCM (in the van when no-start condition first appeared):
Immed. after Key On:
- P0509 (Idle Air Control Circuit High)
After 15 secs cranking:
- P0443 (Purge Valve Control Malfunction),
- P0123 (Throttle Position Sensor Circuit High),
- P0118 (Coolant Sensor Circuit High),
- P1478 (Cooling Fan Driver)
- P1193 (EGR Drive Out Current)
- P0509 (Idle Air Control Circuit High)
If retried this test a few times & only occasionally get P1193 & P1478, but otherwise consistent results

Original PCM reinstalled (the van DID run with it, just lack of power)
Immed after Key On:
- P0508 (Idle Air Control Circuit LOW....THIS IS DIFFERENT THAN ABOVE)
After Cranking 15-20 seconds:
- P0123 (Throttle Position Sensor Circuit High)
- P0118 (Coolant Sensor Circuit High)
- P1193 (EGR Drive Out Current)
- P0508 (Idle Air Control Circuit LOW)

I've double checked the connector on the Idle air motor. Curiously, the code for it changed from P0509 (Circuit High), to P0508 (Circuit Low) when I put the original computer back in.

So what should I try next???

Is there a way to by-pass the Idle Air Control Circuit completely...could it even be the cause of no-start?

Its hard to believe that so many sensors or circuits went bad all at once...so am I'm guessing correctly the codes after cranking are the RESULT of the no start condition? I HAVE considered that one branch of the wire harness might be damaged (poss cause of first PCM failure & maybe all the sensors with codes are bundled together somewhere)...but there's no visible sign of damage and I hate to just start digging into it randomly.

I do have the Haynes Manual and have been trying all the tests I can find over and over without finding anything terribly suspicious....even put a fresh battery in it....still no start.

I vaguely remember removing and cleaning the idle air control motor 2 years ago to resolve some code and get it through AZ emissions, but had no trouble with the Idle Air Circuit since. I'm about to remove it again...maybe just replace it...but $$$ is tight and don't want to just waste it.

What should I try next? I'm getting a little tired of walking!!!

 

Try replacing the map/baro sensor.

 

Frsutratingly, changing the MAP sensor didn't remedy the problem. I also check continuity on all the wires between IAC, MAP & TPS sensors and the PCM connector. Still crank (rough crank, not smooth) but no start.

Any other suggestions are welcome.

 

I'm bumping this because ANY help would be appreciated. My 2001 Grand Caravan 3.3Gas STILL won't start after months of fiddling with it. In addition to the stuff above, I replaced TPS, MAP sensor & battery, dug through wire harnesses looking for shorts (both visually in some questionable harness areas I stripped open and by metering from sensor to the PCM connector). Replacing all these sensors and still getting the error codes is frustrating...and getting ex$pen$ive. I've double checked all fuses and relays in the box and pulled the shroud off the ign switch to check things there. I've gone through the no-start trouble shooting in Haynes manual, checking relays, switches, wires, connectors & sensors, but end up at "investigate some other electrical problem". I even tried banging on the right side of the instrument cluster, as suggested in another post. Despite all this, no start and I'm still getting a bunch of codes when I try to start, but the most prevalent ones are P0123(TPS Circuit High), P0118 (Coolant Temp Circuit High) & P0509 (Idle Control Circuit High). Is there any significance to the order they appear on the code reader??? Is there some kind of voltage regulator I need to investigate with these circuits all being high? Or maybe some "ground" or other "circuit part" common to them all???

Sadly, as a single teacher in Phoenix AZ with huge budget cuts going on...I can't afford (risk) taking it to a dealer.

As a reminder...this whole thing started after a no crank episode....turned the key and nothing...after just driving the van earlier in the day. Finally got it cranking when fiddling with the brake pedal the next day....just the right position and the engine would crank. Now the pedal doesn't seen to be causing any problem (don't have to fiddle with it at all). When I turn the key, I can hear the fuel pump pressurize the system and it cranks just fine...just no spark at the ign module. I also did put the old PCM back in (understanding that it would run rough from the bad #5 inj circuit)...but still get the similar codes with either module.

Other than sledge hammer or blow torch....Please...What else can I try?

Seriously...any practical suggestions are welcome.

 

if yalls a teacher then use some networking and see if yall can finds a smart auto teacher theres gotta be a bunch around pheonix she a big town, or jsut put some more sensers and another pcm at it eventually somthings gotta fix it.

 

Wow, Thanks! Your sarcasm is really helpful.

In my house, we freely offer input all over the net on things we know, defer to other experts on things we're uncertain about and ask questions on things we want to learn. I refuse to stay ignorant when its so easy to get educated.

On this issue, I've been asking everyone I know and everyone THEY know. I've had the van on a Diagnostics machine that misdiagnosed the problem & told me nothing more than my code reader already did...yet tried to convince me I had to replace all my injectors which had already tested fine. I've also had 2 other paid mechanics misdiagnose this problem and leave me with no running van . So I'm taking it into my own hands as a personal challenge to fix this thing.

As I mentioned, it seems reasonable its a short somewhere not obvious...but the PCM, harness, connectors and sensors is a big monster, often very hard to see or expose while buried in the engine....and has probable weak points in the circuit that likely have failed before for others with similar symptoms. I'm just looking for input from some other helpful people that might have been through a similar "adventure".

Its kind of the whole reason for these forums...to SHARE experience...not trashing people for asking reasonable questions when they clearly already have done a ton of work (not lazy), acquired many of their own resources (tools, test equipment, repair manuals, wiring diagrams) and aren't afraid to dig deeper themselves (not just expecting someone else to fix it for them for free)...all the while learning plenty of things along the way.

Today I did find a possible short in the harness behind the Ignition Module, fixed it & metered out that section of the harness for other shorts....but still get codes P0123, P0118, P1193...and now 1598 (new one). I can easily see by inspection and from the wiring diagram that they're all sensors on the same side of the engine and branch of the harness, but the wires seems to check out on that section (though, I'm not assuming the short is there). While checking that everything was plugged in, I did find a section of cracked hose connecting some tubes near what seems to be an evap service port...so I'm off to get some hose to replace it.

Any helpful input on what else I might investigate is appreciated.

 

Before you get hissy DEMANDING people solve your problems... That idea of dealing with a high school auto instructor has a lot of merrit. We have a shop teacher in our town that is first rate and willing to help out destitude people. When he get's stumped, he calls me and bounces ideas off on what to do next. My sharing experiences are the you MUST get your hands on a factory service manual and you MUST get a real scanner so you can analyze the data related to this problem. The issues you have are IMPOSSIBLE to accurately diagnose based on the fact that qualified mechanics, on this board, cannot see all the issues. For example the Master Tech guy, whome is clearly qualified, lead you astray with replacing a part. Even the BEST can't just guess without being able to do a thorough in-person analysis. Just today, I had a customer call that they had a strong gas smell and is seemed the van was using a lot of gas. Well after spending about 10 minutes with them on the phone trying to diagnose the problem (leaky hoses, leaky injectors, etc) The brought it to me. I spent another few minutes diagnosing the problem only to find the cause is they had a 2 gallon gas can in the back that tipped over. The fuel mileage issue was due to long warmup time for the past several days not exceeding 10°F. There is NO ignition module on your van. To me your problem could be one of 100 things. First, the codes should never be counted on a point to start without clearing them then seeing which ones come back. Too many people monkey with the wiring while the key is on and induce bogus codes, then to fix the problem, they are in autozone buying every sensor hoping to fix the problem. 2nd I can't believe you have a corrosion issue in Phoenix, AZ, but since you put forth the effort to check, that's a viable diagnostic proceedure. Then there's a very common problem of a broken flex plate causing these symptoms. However given the lack of adequate equipment, this will be nearly impossible for you to diagnose

 

You can swap out the PCU on the 2002 Caravan? Mine has the check engine light on - my OBD-II reader doesn't see any code and the dealer said there is some internal diagnostic code and they recommend replacing the PCU - 1066$ They said getting one from the wrecker is not an option because it has to have the VIN programmed into it to work (?!). Is he just blowing smoke out his ****?

 

wow take you need a computer and an air bag and yall mite as well just buy another van cuz them 2 thing is worth more than the car.

 

Using Salvage PCM....Here is my personal experience. YES, you can replace the PCM with a salvage one when in a real pinch, B-U-T you have to carefully match up the unit number, the are some considerations about security systems, the mileage will be different on your odometer and there likely will be some "glitches" from mismatched VINs. I used a salvage PCM to drive my van home from 400 miles away and work out frustrating electrical problems after an engine wiring meltdown. HOWEVER, you can order a remanufactured unit with a lifetime warranty through ebay for a little more than buying a salvage unit and a whole lot less than buying a dealer unit. They will make sure you get the right unit AND program it with your VIN and mileage. In my case, the salvage unit was $100 (and that took a bunch of calls to find) and the remanufactured unit is $150. Look for a company with a real street address and a long history with lots of feedback. Its about a 10 minute job to install the replacement PCM...not very scary or messy at all. The PCM is attached to the back of the driver's side headlight housing. Unplug the two large connectors on the side of the PCM by pinching the latches on both sides of the connector and pulling to the left. Remove three bolts on top of the headlight housing to remove the headlamp. Remove two bolts on top of the PCM and one bolt inside the headlight housing, and the unit pulls right out from the top. Reverse procedure to install replacement unit.