GM Powertrain Diagnostic Circuit Check

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2006 Chevy Impala Always start with Strategy Based Diagnosis.

Lets assume you have already verified the customer concern, done a visual inspection, and checked for bulletins.

As a result you are led to the Diagnostic Circuit Check.

Locate the Diagnostic System Check on the AC Delco website and follow the procedure to answer the following questions. Your working

on a 2006 Chevy Impala with a 3.5L engine.

Diagnostic System Check1. Once you have accessed the Diagnostic System Check on the ACDelco Website record the Document ID number (top right hand side of page) ___________________.

Diagnostic System Check. Scan tool powers up.

Control Module Check

Control Module Check

Control Module Check

Control Module Check

Control Module Check

Control Module Check

Control Module Check

SPID for Identification

Are all the Module Communicating?

Compare the SPID label to the Data Link Connector Schematics to answer the following: 2. Do we have U2K? _________3. How about KA1? ________4. How about UE1? ________5. How about JL9? _________6. As a result does the vehicle have a heated seat module? ___________7. Does the vehicle have a digital radio receiver? _____8. Does the vehicle have a VCIM? _____________9. List all the modules the vehicle has. This would include both low and high speed Lan devices. ____________________________________________________________________________________________________________________________________________________________________________________________________________________________________10. Base on the previous 4 slides are all the modules communicating that should be? ___________

Lets Select View All DTC’s.

11. Do we have a U1814 or a B1428 based on the following slide? ______________________

Now lets check Power Mode Mismatch.

Power Mode Mismatch12. Does Power Mode Mismatch appear normal? ____________

Security Lamp Check13. Base on the next 2 slide does the Security Bulb operate correctly? _____________

Which one is the security light? Key first turned ON.

After Vehicle Bulb Check

Vehicle Cranks and Runs. 14. Do we need to Capture Information? _________________

Capturing Information

The ECM has a Code.15. Has this code caused the MIL to illuminate? ____________16. What type of code is this? (A or B) ________17. Will we have a Freeze Frame wrote for a 1 trip failure ?_______18. Will we have a Failure Record wrote for a 1 trip failure? _______

Notice a Failure Record but NO Freeze Frame.

19. How many Frames is a Failure Record? ____________

Notice the MIL is now requested after starting the vehicle twice with the fault. We will also have a freeze frame as a result. Let’s go to the DTC Chart since this is a current code.

DTC Chart P0106

20. Record the Document ID number for the DTC Chart P0106. ______________21. Referring to the chart answer the following: a. What are the conditions for setting this code? ______________________________________

______________________________________22. When does the PCM illuminate the MIL? ________ _________________________________________

We have performed the Diagnostic Circuit Check.

MAP appears to be plugged in and a smoke test reveals no leaks in the intake.

23. Does the Pre-catalyst oxygen sensor appear to be operating normally? _________________

24. Lets disconnect the MAP and check 5-volt reference circuit. Are we within range? ___________25. What should the voltage be within? ___________________

26. Is the MAP kPa within range? ________ (Baro is highlighted but you want to use MAP Sensor kPa)27. According to service information it should be less than? _____ Remember we have the sensor disconnected.

We now jump the 5 volt reference to the signal circuit.

Notice are fused jumper wire. 28. What is being used for a fused jumper wire? _______________

29. This is what the MAP reads now on the scanner. Is this

correct? ________ (Don’t use BARO value). 30. According to service information it should be greater than? ___

We are going to turn off the ignition and allow the PCM to power down. This takes approximately 30 seconds.

31. Lets check resistance of the low reference circuit. Using service information go back to Schematics and Wiring Diagrams. Select Engine Control Schematics and MAF/IAT, MAP, and ECT Sensors. What is the Low Reference wire color to the MAP sensor? _______ 32. What is the Letter at the MAP sensor for this wire? _____________33. What is the Document ID? __________34. Is the resistance correct as indicated below? ________

MAP Removed

Orange seal removed and hand vacuum pump hose attached to port.

Notice vacuum gauge reads 2” with NO vacuum applied.

With no vacuum applied look at MAP reading.

1” of vacuum applied

35. How much should the kPa change? _____________36. Does it decrease in pressure with vacuum applied? _______37. Should it decrease in pressure with vacuum applied? ______

At 3” of vacuum look at the kPa.

38. What do you think of MAP Sensor? ______________________________________________________________________________________________________________