Ive been without my truck for a week now because of a ecm problem. i havent been able to center it down exactly how the problem occured but i do know there is something wrong with my ecm.

Is there anyway to test to see if your ecm is fried? and is there such thing as putting it in safe mode?

 

A dealer can see if it will display it's readouts, fault codes, and make changes in programming. Generally if it can be upgraded, it is good. Dealer also has a tool (actually a simple cable arrangement) that allows the VP44 to run engine in a test mode. Results are if cable will allow VP44 to operate engine the IP is good and something else is in question.

 

....there is also a way to bench test most controllers. I've done it on one ECM and too many PCM's over the years to count. Jumper wires, old ALDL connector, 12 volt source, DRB, wiring pinout diagram required. This will only help you if you have a "no response" condition. Sometimes shorted wiring, sensors can pull the controller out of the loop. This bench test will only let you know in which direction you need to go.

 

When you turn key on does the wait to start light just flash? if it does then ecm has loss programing.
No Start. The Wait To Start Light Is Flashing. Check ECM Operation.;The DRBIII® will not communicate with the ECM. Code p1694 set in the JTEC. ECM powers, ground and switched ignition check ok. CCD Buss wiring between the JTEC and the ECM check ok. See the appropriate Powertrain Diagnostic procedure manual for code P1694 if information is needed to check CCD Buss and powers and grounds.
System or Component Flickers / Flashing,Engine Cranks;Customer Concern (No DTCs),DTC / Error Message,No Response,Programming / Flash;ECM,Wait To Start Light;Yes - Continuously
Recommendation Try the flash recovery procedure in TSB 18-020-02. If the ECM still will not respond to the DRBIII® replace the ECM

 

the wait to start does not even turn on. the over head just says CCd and the odometer flashes. and my scanner doesnt even regester anything, it just keeping going through the 1st step which is turn your key forward.

 

NO BUS flashes in odometer => Check for 5 volt circuit short to ground or loose ground at pcm...;What is the problem with the instrument panel/cluster? >> odometer In what area is the electrical problem? >> Cluster Have you checked for 5 volt circuit short to ground and loose PCM ground circuits? >> NO What is the problem with the odometer? >> "No Bus" in odometer
System or Component Customer Concern (No DTCs);Instrument Panel / Cluster,Odometer
Recommendation Check for 5 volt circuit short to ground or loose ground at pcm... The root cause is usually one of the two 5 volt supplies shorted to ground. If so, this will lock up the PCM and you will experience a die out, NO BUS, and a NO RESPONSE problem. The PCM will put out 5 volts on pin a17 (k7) and pin b31 (k6) when the PCM is powered up. See page 8w-80-59 of the 2000 XJ Service Manual, check pins 2 & 22 (power) and pins 31 &32 (ground). if ok then back probe pin 17 (5v) and pin 31 (c2-5v also). If there is no voltage coming out of these drivers, remove the wire and then probe the pin, if the voltage is 4.5 - 5.0 volts then the circuit is grounded, usually it ends of being a shorted crank sensor. As far as the SCI, see page 8w-80-61, the sci transmit will have 12 or 5 volts sent from the DRB3 when accessing the PCM, the SCI receive will have 5 or 12 volts on it just when the key is turned on. the pcm supplies the voltage on the SCI receive, the drb3 supplies the voltage on the SCI Transmit. Its unlikely, but there have been cases where the sci was shorted to VOLTAGE causing the PCM to lock up. Note: Don't forget that components attached to these pull up circuits such as cam, crank, tps, and map sensors, to name a few, can also be shorted internally causeing this condition.

 

The two main areas of concern are either the JOINT CONNECTER #7 located undert the dash, or Connecter C134, it as well is locate in the side knee blocker area. Connecter C130 is loacted in the engine compartment and it too contains ccd bus wires. Check the PCM grounds as well, a loose pcm ground has caused multiple ccd issues, this usually more likely when any engine work has been done prior. Though anything in the ccd bus system can cause this problem, there is a 50 % probability that the PCM is at fault, this based off our field records and STAR finding.

 

so which wires should i look for under the dash?