ECM troubleshooting

Tiny
14CASPER88
  • MEMBER
  • 2002 CHEVROLET TRAILBLAZER
  • 4.2L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 160,000 MILES
A two foot extension was left under the hood and while driving it got grounded out from positive terminal to the ECM! I replaced with ECM with all the same numbers on it and still nothing. I have all the dash lights come on accept the engine light, I got no fuel pump, no starter, etc.
Saturday, August 11th, 2018 AT 1:49 AM

2 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,690 POSTS
It sounds like the PCM is not getting power. Lets check by following this guide and checking out the PCM wiring diagrams below.

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

Check power at fuse #22, #10 and #47 here are the engine wiring diagrams and the fuse location.

Check out the diagrams (below). Let us know what happens and please upload pictures or videos of the problem.

Cheers, Ken
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Monday, August 13th, 2018 AT 2:05 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good afternoon.

Did you have it flashed or programmed to your truck? Without that it is like a computer with no operating system.

New or used PCM?

Roy

This is the procedure for the flash:

IMPORTANT: Do NOT program a control module unless you are directed by a service procedure or you are directed by a General Motors Corporation service bulletin. Programming a control module at any other time will not permanently correct a customers concern.

Ensure the following conditions are met before programming a control module:
- Vehicle system voltage
- There is no charging system concern. All charging system concerns must be repaired before programming a control module.
- Battery voltage is greater than 12 volts but less than 16 volts. The battery must be charged before programming the control module if the battery voltage is low.
- A battery charger is NOT connected to the vehicle's battery. Incorrect system voltage or voltage fluctuations from a battery charger, may cause programming failure or control module damage.
- Turn OFF or disable any system that may put a load on the vehicle's battery.
- Twilight sentinel
- Interior lights
- Daytime running lights (DRL)-Applying the parking brake, on most vehicles, disables the DRL system.
- Heating, ventilation, and air conditioning (HVAC) systems
- Engine Cooling fans etc.
- The ignition switch is in the proper position. The scan tool prompts you to turn ON the ignition, with the engine OFF. Do NOT change the position of the ignition switch during the programming procedure, unless instructed to do so.
- All tool connections are secure.
- RS-232
- The connection at the data link connector (DLC) is secure.
- Voltage supply circuits
- DO NOT disturb the tool harnesses while programming. If an interruption occurs during the programming procedure, programming failure or control module damage may occur.

REMOTE PROGRAMMING
1. Turn OFF the ignition.
2. Install the Tech 2(TM) to the data link connector (DLC).
3. Turn ON the ignition, with the engine OFF.
4. Turn OFF all vehicle accessories.
5. With the Tech 2(TM), select Service Programming.
6. Identify vehicle information as requested by the Tech 2(TM)
7. Select the type of module you are programming.
8. Select the type of programming to be performed.
9. Verify the displayed VIN with the vehicle VIN. If the displayed VIN does not match the actual VIN, write down the actual VIN and correct the VIN at the Techline(TM) terminal.
10. When complete, Exit Service Programming.
11. Turn OFF the Tech 2(TM) and disconnect the Tech 2(TM) from the vehicle
12. Turn OFF the ignition.
13. Connect the Tech 2(TM) to the Techline(TM) terminal.
14. Select Service Programming.
15. Select Tech 2(TM) as the tool you are using.
16. Select the type of programming to be performed.
17. Verify the displayed VIN with the vehicle VIN. Correct the VIN as necessary.
18. Select the type of module you are programming.
19. Identify what type of programming that you are performing.
- Normal-This type of programming is for updating an existing calibration or programming a new controller.
- Vehicle configuration Index (VCI)-This selection is used if the vehicle VIN is unavailable or not recognized by the Techline(TM) terminal. Observe, you will need to contact the Techline(TM) Customer Support center to use this option.
- Reconfigure-This is to reconfigure a vehicle, such as tire size and axle ratio changes.
20. Select the appropriate calibration file.
21. Ensure all connections are secure.
22. Select Reprog to initiate the download of the new calibration to the Tech 2(TM).
23. After the download is complete, turn OFF the Tech 2(TM).
24. Disconnect the Tech 2(TM) from the Techline(TM) terminal.
25. Install the Tech 2(TM) to the data link connector (DLC).
26. Turn ON the Tech 2(TM).
27. Turn ON the ignition, with the engine OFF.
28. Select Service Programming.

IMPORTANT: DO NOT turn OFF the ignition if the programming procedure is interrupted or unsuccessful. Ensure that all the PCM and DLC connections are secure and the Techline(TM) operating software is up to date. Attempt to reprogram the control module. If the control module cannot be programmed, replace the control module. Refer to Powertrain Control Module (PCM) Replacement.

29. Select Program.
30. After the download is complete, EXIT Service Programming.
31. Turn OFF the ignition for 30 seconds.
32. Turn OFF the Tech 2(TM).
33. If a control module is replaced the following service procedures must be performed:
- The Crankshaft Variation Learn Procedure
- The Engine Oil Life Reset Procedure
- The Idle Learn Procedure
- The Inspection/Maintenance Complete System Set Procedure
- The Vehicle Theft Deterrent Password Learn Procedure
- The TP Sensor Learn Procedure

PROGRAMMING VERIFICATION
1. With a scan tool, clear the DTCs.
2. Attempt to start the engine.
3. Repeat the Service Programming procedure if the engine does not start or operates poorly. Perform the following procedures before programming the PCM:
- Ensure the control module and DLC connections are OK.
- Ensure the Techline(TM) operating software is up to date.
- Ensure the calibration part number is correct for the vehicle.
4. Attempt to program the control module. If the control module still cannot be programmed properly, replace the control module. Refer to Powertrain Control Module (PCM) Replacement. You must program the replacement control module.

BEFORE PROGRAMMING A CONTROL MODULE

IMPORTANT:
- Do NOT program a control module unless you are directed by a service procedure or you are directed by a General Motors Corporation service bulletin. Programming a control module at any other time will not permanently correct a customer's concern.
- The Off-Board Programming is used in situations where a control module must be programmed without having the vehicle present. The Off-Board Programming Adapter must be used to perform the Off-Board Programming procedure. The adapter allows the control module to power up and allows the Tech 2(TM) to communicate with the control module.
- DO NOT disturb the tool harnesses while programming. If an interruption occurs during the programming procedure, programming failure or control module damage may occur.

Ensure that all connections are secure at the following locations:
- The Off-Board Programming Adapter
- The Tech 2(TM)
- The control module
- The Techline(TM) terminal

OFF-BOARD PROGRAMMING
1. Obtain the VIN of the vehicle for which the control module is being programmed.
2. With the Techline(TM) terminal, select Service Programming.
3. Select Tech 2(TM), Reprogram ECU, and Off-Board Programming Adapter as the ECU location.
4. Connect the control module, Off-Board Programming Adapter, and the Tech 2(TM) as described on the Techline(TM) terminal. Ensure you use the correct harness connector from the Off-Board Programming Adapter kit.
5. With the Tech 2(TM), select Service Programming Request Information function. The Tech 2(TM) communicates with the control module and receives the access code.
6. With the Tech 2(TM), exit the Service Programming Request Information.
7. Disconnect the Tech 2(TM) from the Off-Board Programming Adapter.
8. Connect the Tech 2(TM) to the Techline(TM) terminal.
9. Turn ON the Tech 2(TM).
10. With the Techline(TM) terminal, enter the VIN of the vehicle that will be receiving the control module.
11. The Techline(TM) terminal will display the message, attaching to database.
12. Identify what type of programming that you are performing.
13. Select the appropriate calibration file.
14. Ensure all connections are secure.
15. The Techline(TM) terminal displays a summary screen that summarizes your selections. After confirming you choices, the Techline(TM) terminal automatically loads the calibration files to the Tech 2(TM).
16. After the download is complete, turn OFF the Tech 2(TM)
17. Disconnect the Tech 2(TM) from the Techline(TM) terminal.
18. Connect the Tech 2(TM) to the Off-Board Programming Adapter.
19. With the Tech 2(TM), select Service Programming.

IMPORTANT: DO NOT turn OFF the Off-Board Programming Adapter if the programming procedure is interrupted or unsuccessful. Ensure the control module and the Off-Board Programming Adapter connections are secure and the Techline(TM) operating software is up to date. Attempt to reprogram the control module. If the control module cannot be programmed, replace the control module.

20. With the Tech 2(TM), select Program.
21. After the download is complete, exit Service Programming.
22. Turn OFF the Off-Board Programming Adapter.
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Monday, August 13th, 2018 AT 2:06 PM

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