Hey everyone, I am new to the forum and this is my first post. I have a 1995 Chevy k2500 6.5l Turbo with 143000 miles on it. Recently replaced PMD and relocated, new fuel filter and new turbo boost sensor. Truck runs great as long as SES light does not come on. When it SES light does come on truck goes into limp mode and I have to shut engine off and restart. I have checked the codes and these are the ones that keep coming up, I have cleared them several times and these are are the ones to keep coming back. Codes; 17,18,22,27,35,36,65,84 and 99. Codes 65,84 and 99 do not always come back though.

I have cleaned the grounds and installed a clear fuel line to check for air. All seems OK. I have researched the codes and am not sure where to start next? I know there are a lot of APP codes so should replacing that be my next step? As I stated when SES light is off it runs great and I may not have any problems for several days and then I may have a day when it throws codes several times either on startup or when driving.

Any help would be greatly appreciated as this is the most trouble I have had with this truck.

 

DTC 17 - High Resolution Circuit Fault
DTC 18 - Pump Cam Reference Pulse Error
DTC 22 - Accelerator Pedal Position 1 Circuit Low
DTC 27 - Accelerator Pedal Position 2 Circuit Range Fault
DTC 35 - Injection Pulse Width Error (Time Short)
DTC 36 - Injection Pulse Width Error (Time Long)
DTC 65 - Accelerator Pedal Position 3 Circuit Range Fault
DTC 84 - Accelerator Pedal Position Circuit Fault
DTC 99 - Accelerator Pedal Position Sensor 5-Volt Reference Problem



Always start with the lowest # codes and work your way up.

The first 2 could be related to a failing optical sensor electronic noise filter?
remove it and place ferrite core around each OS sensor wire-plug the harness directly into the OS without the filter.

the APP codes make me think there is a ground problem so make sure that the grounds at the back of the intake,all 3 of them are clean and secure and fastened to good grounding location like pinched between the flats of a water blockoff plate stud and another nut,I would consider adding another ground wire from there to a battery ground.

The pulse width codes make me think that the IP harness ground needs attention and MUST be fastened to the IP top cover clean and secure,adding a ground from there to the drivers side battery ground won't hurt as well as adding a ground to the PMD heatsink to a battery ground.

You may still need to diagnose the APP,google 6.5 diesel APP tresting.

 

Thanks for the reply,

Checked all my grounds again today. cleaned ground cable that goes down to frame by starter. Going to get some wire and add extra grounds on stud at back of intake and heat sink. Changed out my glow plugs as it is supposed to get cold here in Ohio. Thats all I had time for today.

 

I also add a few more grounds and do the Allen screw battery bolt change.

Use lots of Kopper kote.

Read the post I put on grounds on the 94. The added grounds to the battery box bolt, the frame by the starter and the heater blower to dash bolt all seem to be good adds.

I usually use 10 ga wire for everything, I solder and/or heat shrink almost all connections

 

I have a 94 Chevy 4x4 6.5 diesel 10 trannys later goes into limp mode shudders when take off after that shifts perfect but when it shudders I turn key off then it's fine I drove it for awhile like that burned the 4l80e up took it to shop got a complete rebuild did it again I'm thinking the harness bc when I pulled it out stupid me dropped old tranny pulled harness down with it possible broke or an issue plz help