Service engine light does not turn on after testing another IPDM/ER?

MALLYBOY

MEMBER
2005 INFINITI G35
3.5L
V6
2WD
AUTOMATIC
102,567 MILES

Service engine light stop illuminating after testing another IPDM/ER on the vehicle while I was troubleshooting a fault. Then when I put back the original IPDM/ER of the vehicle, still service engine light didn't illuminate.
I have checked all fuses and relay and all test good. Could it be from the communication line? And which module is responsible for this light to illuminate?

7 Replies

KEN L

MASTER CERTIFIED MECHANIC
42,877 POSTS

The PCM is responsible for turning the check engine light on and off. Can we see if fuse# 89 in the IPDM has power? Here is a guide to help and the wiring diagrams for the computer data lines so you can see how the system works. Have you run the codes?

https://www.2carpros.com/articles/how-to-check-a-car-fuse

and

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Check out the diagrams. (Below) Please let us know what happens.

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Friday, July 22nd, 2022 AT 9:51 AM

MALLYBOY

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I have checked the relay and fuse and it check okay, there's power to the fuse #89.

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Friday, July 22nd, 2022 AT 10:39 AM

KEN L

MASTER CERTIFIED MECHANIC
42,877 POSTS

Okay, let's do a CAN scan to see what comes up, you can get a CAN scanner from Amazon for about $30.00.

Here is a video to show you how:

https://youtu.be/u-4syLc-ifQ

Here is a scanner link:

https://amzn.to/3o41KcZ

Please let us know what happens.

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Saturday, July 23rd, 2022 AT 11:10 AM

MALLYBOY

MEMBER
300 POSTS

I have come to tell you that I have seen the problem why Service Engine Light has not been illuminating. I first checked fuse #77 and there was power, I checked the fuses terminals and there was power. The problem is with ECM Relay the grounding path of the ECM is not energizing the relay, then I jumper the terminals with jumper wire and turn ignition switch on and the service engine light come on. Thanks for assistance.

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Tuesday, July 26th, 2022 AT 12:16 PM

KEN L

MASTER CERTIFIED MECHANIC
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So, is it fixed? Did you have to run a new wire?

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Wednesday, July 27th, 2022 AT 12:38 PM

MALLYBOY

MEMBER
300 POSTS

It requires replacing the ECM because if I used wire to ground the relay terminal that leads to ECM TERMINAL 111 and to the negative battery cable, the relay will close, and the service engine light will come on. If I remove the wire, it will go off.
Therefore, I had pulled the white wire from ECM connector and feed from throttle control relay terminal of ECM connector, and it didn't work.
If I ground it to the negative battery terminal, the relay will always be on, I haven't gotten idea how to do it so that ignition will energize the relay when turn on.

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Thursday, July 28th, 2022 AT 2:40 AM

KEN L

MASTER CERTIFIED MECHANIC
42,877 POSTS

Got it, here are the instructions for changing the ECM out. It will need a VIN programmed into the new unit which you can get from eBay. Check out the diagrams (below). Please let us know what happens.

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