Have an Chevy K2500, from 1992 with 6.2 diesel.
While driving the Service Engine Soon lamp comes on, I have tried to connect the A and B terminal on the diagnos,but I don't get any response from the lamp.
From what I know there is no ECU on an 6.2 diesel.
Can anyone help me with this.
Don't have any owner's manual of my truck.


Jan-Tore
:help:

There is an ECM, pull the glovebox out and you will see it laying back there.
Does virtually nothing as far as the engine is concerned, has only a small role in tranny operation if yours is automatic. I had a '90 model 6.2 auto, I took it out and drove with it sitting in the pass seat, you couldn't tell the difference.

Truck has an Auto tranny, TH700.
When the lamp is on, I notise an slight differens in gearshifting.
But, is there any ECM on the tranny.
Does anyone have an clue about this. ?????


Jan-Tore

I may have a manual at home that will shed some light, will check tonight. Fred

My information lists the option code of "LH6", which is the light duty truck RPO (Regular Production Option) code. This RPO indicates the vehicle has an ECM that electronically controls EGR (Exhaust Gas Recirculation), TCC (Torque Convertor Clutch), Cold Advance and Glo-Plug operation.

The ECM uses inputs from Coolant Temp Sensor, Throttle Position Sensor, Engine Speed Sensor and the Manifold Absolute Pressure Sensor.

It can affect trans operation because it controls the convertor clutch lockup.

You should be able to retrieve codes by using a jumper wire to connect terminals "A" and "B". These are the two terminals in the upper right corner of the ALDL under the dash. (black plastic connector with two screws holding it in place) The ALDL has 12 sockets for wire terminals, two rows of six. It faces toward the floor, just under the center of the dash. Looking up, you should be able to see which terminal slots are occupied with a brass wire connector.

Jumper the end two connectors and watch the "Check Engine" light. (Key on, engine off) Turn the key off while you are connecting and/or disconnecting the jumper wire. When you have jumpered the correct two terminals, it will begin to flash. It will flash a "Code 12", followed by any additional codes it has stored. It flashes the code in sequence. One flash, followed by a short space and then two flashes. You count the flashes, "One, One-Two", that translates to "12". It will repeat this three times, then wait a second and begin flashing any additional codes.

Let me know by posting the codes and we'll go from there on the diagnosis. If you could find a shop manual, it explains all of this. It sounds more complicated than it really is. Hope this helps, Fred

Thanks for that info, I will try it when I get home from vacation.

Jan-Tore

Let us know what gives with it.

Have this two codes on my truck.


DTC 21 accelerator pedal position 1 circuit high
DTC 32 egr circuit error

anyone who have some info about this.

Jan-Tore