1996 van 3500 Cant comminicate with computer

salesbig · #1 06-17-2009, 04:59 PM

1996 dodge ram van 3500
The check engine light is on. When they mechanic try to hook up the computer there was no communication
Any thoughts?

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kev2 · #2 06-17-2009, 06:03 PM

remote starter, yes-no?
have you checked ALL fuses, under dash and under hood?
there is not a "no buss" message is there?
try the scanner on another vehicle-

OBD connector. probe with DVOM
top row 1-8 driver door is 1
bot row 9-16 driver door is 9

CK Pin 2 - J1850 Bus+
CK Pin 4 - Chassis Ground
Pin 5 - Signal Ground
Pin 6 - CAN High (J-2284)
PiN 7 - ISO 9141-2 K Line
Pin10 J1850 Bus
Pin 14 - CAN Low (J-2284)
Pin 15 - ISO 9141-2 L Line
CK Pin 16 - Battery Power

SOMETIMES THIS WORKS ...
Turn the ignition key until the digital odometer displays, repeat three times in succession and then back to "On" (On/Off, On/Off, On/Off, On). At the fourth "On" the odometer will be replaced with codes. If no codes are present then "Done" will appear.

salesbig · #3 06-17-2009, 07:36 PM

no digital od. no bad fuses. no remote start.. ill check the pins..
thanks.
just in case this doesnt work.. anyone else have any ideas?

alloro · #4 06-18-2009, 09:32 AM

If the fuses are good, you either have a broken wire issue or a bad computer.

salesbig · #5 06-21-2009, 08:25 PM

Computer seems to be good, i disconnected the battery, re-connected and the check engine light came off. then 15 miles later it came back on..
Anyone know how to check the wires? any pictures of how the wires run from the obd female connector to the computer?
thanks

salesbig · #6 06-21-2009, 08:37 PM

Computer seems to be good, i disconnected the battery, re-connected and the check engine light came off. then 15 miles later it came back on..
Anyone know how to check the wires? any pictures of how the wires run from the obd female connector to the computer?
thanks

alloro · #7 06-21-2009, 08:57 PM

Quote:

Originally Posted by salesbig

When they mechanic try to hook up the computer there was no communication
Any thoughts?

Any chance your mechanic's code reader is no good, or that he was using an incorrect cable?

salesbig · #8 06-22-2009, 08:47 AM

Quote:

Originally Posted by alloro

Any chance your mechanic's code reader is no good, or that he was using an incorrect cable?

No.. i even bought one for myself.. he tried 2 units..

kev2 · #9 06-22-2009, 08:55 AM

i posted the obd connector pinouts above.
check that bat+ and ground pins..

lets be clear - no communication? is not the same as not showing code..

removing battery willnot clear codes they are still in memory

salesbig · #10 06-22-2009, 09:59 AM

Quote:

Originally Posted by kev2

i posted the obd connector pinouts above.
check that bat+ and ground pins..

lets be clear - no communication? is not the same as not showing code..

removing battery will not clear codes they are still in memory

when you disconnect the battery the check engine light went off. came back on about 5 miles later. So im thinking the computer is good.
So if im wrong please let me know.