[R&Wpowerstroke]

This is my first time posting but I'm not sure what else to do about the problem I'm having with my truck. I have a 1996 Xlt and can't figure out what to do with trying to figure out whats wrong with my truck. Me and my buddy went and put it on IDS and there were no codes until we did a key on key off test and the only code that came up was p1667. Its not the IDM because we switched it out with another truck of the same year and it didn't change a thing. So I'm basically left with it being a possible short somewhere or the PCM is bad. i want to check if it is a short before i go and buy a PCM. I don't have a breakout box and am wondering what to do next. I just want some input on this.

 

[Patrick Feeley]

I'm going to post the pinpoint tests for the Cylinder Identification (CID) circuit problems. You can read it to see if there is anything you can do without a breakout box (which you only really need if you are instructed to have the breakout box connected to the PCM ... you can probe harness pins for the PCM connector if it istructs you to leave the PCM disconnected from the breakout box). I only posted the V-series of tests and not the U-series or W-series since you stated you are only showing the P1667 code. Here goes (kinda long):

V1 DIAGNOSTIC TROUBLE CODE (DTC) P1663

DTC P1663 indicated that the PCM has detected a failure on the CID line. Possible causes:

-- Open/short in CID circuit
-- IDM
-- PCM

Check for other codes. Key on, engine off. Perform KOEO On-Demand Self-Test and retrieve Continuous DTCs. Was only DTC P1667 present?

Yes: If DTC P1667 was present, Go to «V2».

No: If DTCs P1663 and P1667 are set together, with or without DTC P1668, GO to «U6».

If DTC P1298 is also present, REPLACE the IDM.

If DTC P1662 is also present, GO to «W1».

V2 CHECK VOLTAGE ON CID CIRCUIT 817 (Y/LB)

Install breakout box, connect PCM to breakout box. Key on, engine off.
Measure voltage on Circuit 817 (Y/LB) between PCM Test Pin 96 and ground Pins 25, 51, 76, 77, 91 and 103. Is voltage of 0.6 ± 0.1 volt present?

Yes: GO to «V3».

No: Voltage of less than 0.5 present, GO to «V4».

Above 4.0 volts is present, Go to «V5».

V3 PERFORM AN OUTPUT STATE CHECK

Key on, engine off. Perform KOEO Output State Self Test, toggle outputs by pressing and releasing the accelerator pedal. Measure voltage between PCM Test Pin 96 and ground Pins 25, 51, 76, 77, 91 and 103. Did the output voltage toggle from 0.6 ± 0.1 volt to B+ volts?

Yes: Intermittent, GO to «V8».

No: REPLACE the PCM. RESTORE vehicle. CLEAR DTCs and RETEST.

V4 CHECK FOR OPEN ON CID CIRCUIT 817 (Y/LB)

Key off. Disconnect the PCM from breakout box. Disconnect the IDM connector. Measure resistance on Circuit 817 (Y/LB) between PCM Test Pin 96 and Pin 16 on the IDM harness connector. Is resistance less than 5 ohms?

Yes: GO to «V6».

No: REPAIR open in Circuit 817 (Y/LB). RESTORE vehicle. CLEAR DTCs and RETEST.

V5 CHECK CID CIRCUIT 817 (Y/LB) FOR SHORT TO POWER

PCM disconnected. Key on, engine off. Measure voltage on Circuit 817 (Y/LB) between PCM Test Pin 96 and ground Pins 25, 51, 76, 77, 91 and 103. Is voltage present?

Yes: REPAIR short to power on Circuit 817 (Y/LB). RESTORE vehicle. CLEAR DTCs and RETEST.

No: GO to «V7».

V6 CHECK CID CIRCUIT 817 (Y/LB) FOR SHORT TO GROUND

Key off. Measure resistance between PCM Test Pin 96 and ground Pins 25, 51, 76, 77, 91 and 103. Is resistance greater than 10,000 ohms?

Yes: GO to «V7».

No: REPAIR ground short on Circuit 817 (Y/LB). RESTORE vehicle. CLEAR DTCs and RETEST.

V7 CHECK PCM OUTPUT STATE FUNCTION

Key off. Connect PCM to breakout box. Perform KOEO Output State Test. Measure voltage between PCM Test Pin 96 and ground Pins 25, 51, 76, 77, 91 and 103 while pressing and releasing accelerator pedal. Did the output voltage toggle from 0.5 ± 0.1 volt to 0.0 volt?

Yes: REPLACE IDM. RESTORE vehicle. CLEAR DTCs and RETEST.

No: REPLACE PCM. RESTORE vehicle. CLEAR DTCs and RETEST.

V8 INTERMITTENT

Key off. Restore vehicle. Clear DTCs. Turn key off, then turn key on. Perform KOEO On-Demand Self Test. Did DTC P1663 reset?

Yes: REPLACE the PCM. RESTORE vehicle. CLEAR DTCs and RETEST.

No: Unable to duplicate failure. RESTORE vehicle. CLEAR DTCs and RETEST.

Hope that is some help. Cheers!

 

[R&Wpowerstroke]

Thanks I am going to try this Tomorrow and see how it goes. I'll post on here to let you know if I can get it foxed with that.

 

[61ford]

I'm going to post the pinpoint tests for the Cylinder Identification (CID) circuit problems. You can read it to see if there is anything you can do without a breakout box (which you only really need if you are instructed to have the breakout box connected to the PCM ... you can probe harness pins for the PCM connector if it istructs you to leave the PCM disconnected from the breakout box). I only posted the V-series of tests and not the U-series or W-series since you stated you are only showing the P1667 code. Here goes (kinda long):



Hope that is some help. Cheers!

Where is u6?

 

[Patrick Feeley]

I only posted the V-series of tests and not the U-series or W-series since you stated you are only showing the P1667 code.

Which code(s) are you showing and what year truck? Here are the Introductions and Pinpoint Tests for T, U, V, & W. Cheers!

 

[Patrick Feeley]

Can someone verify that they can open the pdf files in my above post? They open for me with no issue. Cheers!

 

[shoebear]

Hi Patrick! They look good to me!

When I click on them my browser (Opera) prompts me to save them, so I did so for all 8. Then I opened each one with a PDF viewer, and they opened fine with no problems.

 

[61ford]

I got it. Firefox was blocking office from opening them.

 

[Patrick Feeley]

Thanks shoebear!

61ford, there's plenty to go through there. I hope they help! Cheers!