As title states im in serious need of help. Was driving along in my 98 12 valve when i lost all input from the cluster. I have done self check and the cluster passed and gives codes 920-921-999. I have cleaned grounds in engine bay, have a brand new vin coded pcm swapped in a different engine harness that i went through and cleaned every connection and re wrapped. I have swapped in a cluster from another 98 as well as a 99 24 valve. I have un plugged modules without any change checked relays swapped them around as well as checked fuses. One thing that is odd is usually everything i read with regards to no bus is the lack of a WTS light. On my truck KOEO the WTS and OD off are lit up immediately and dont go out then after a bit i get ABS/Brake, Low Fuel, and the seatbelt warning light. I really need help figuring this out to get my cluster back, this happened maybe 15 mins after i was messing with my pillar pod guages and one of then shorted out and popped the fuse tap that it was in, fuse 14 in the junction block but everything else worked fine and I’ve replaced that fuse and my glow shift guages function properly as well as all other electronics on the truck. Any help is greatly appreciated 

I have an in cab meter thats in my switch panel for lights its at like 14.7v when running without lights but im going yo disconnect it when i put the pcm in and see if it gives me any response before hooking everything back up. When everything was working it was at 14.5 i think 

PCM came in today so fingers crossed although im not getting my hopes up

No change so i think i should give up

So after all that it still doesn't work?

 

Check for good continuity on the ccd wires from the PCM to ABS and then check continuity from ABS to cluster.

Yup still not working i will check tonight

Infinite continuity between PCM and ABS Pin 29/30 on C3 PCM and Pin 3/7 on ABS and i checked pin 29 to 3/7 and 30 to pin 3/7 just to be safe and nothing 

Open up the harness over the engine and follow the ccd wires.

On a 24valve they have 3way t that goes to ECM , not sure about yours.

I had it all unwrapped and i cleaned all wiring and inspected it all ill have to look at it

I put the pcm back in this morning i have it just sitting with on screw holding it loosely for now i turned the key and the OD light isnt on anymore i have the ESS un plugged im gonna purchase a new one and gap it when i get a chance but the WTS still is staying on very curious

So i unplugged and plugged the pcm

C3 in a couple times and OD light came back on im wondering if maybe the pcm isnt getting good connection should i use and grease or anything 

You can use dielectric grease, but I don't think it will help your situation.  The dielectric grease primarily helps keep out moisture and reduces the likelihood of oxidation on the pins. 

 

I would carefully inspect the multi-pin connectors for any spreading of the the female terminal and inspect for any wires that may be partially pushed back inside the connector.

 

- John

Ill look at the plugs and see the pins looked ok when i cleaned the harness but ill look more thoroughly at it again

I dont see any issues with the plugs on the female ends 

On 3/8/2024 at 4:10 PM, KyleM94 said:

Infinite continuity between PCM and ABS Pin 29/30 on C3 PCM and Pin 3/7 on ABS and i checked pin 29 to 3/7 and 30 to pin 3/7 just to be safe and nothing 

My diagram shows pcm 28 to ABS 10 for CCD- . Pcm 30 to ABS 3 for CCD+.

 

Double check and verify your ohm meter and test leads are working by touching them together.

Open up the large bulkhead connector and check the 3 twisted pairs of wires. Look closely at both mating connectors for bent pins or spread sockets. Lightly tug each wire and make sure they are locked in to the plastic good.

 

See photo.

 

 

Will do i should be home for a but after today its outage season so work is pretty strong atm. Ill pull that plug and see whats what and check my continuity

Sorry for the gap between replies i checked those pins continuity is 0 ohms. I pulled the connector didnt see any spread pins or anything wires all seem connected good into the plastic. Im not sure what else i can do. This summer ill be pulling the dash and motor to put in a 24v and all wiring modules etc. is there a way i can run cruise control and ac without the PCM until then or no?