GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2002 🢒 Safari - 4WD 🢒 Engine 🢒 Engine Electrical 🢒 DTC P0601, P0602, P0603, P0604, P0605, P0606, P0607, P1600, P1621, P1627, P1680, P1681, P1683, or P2610

Circuit Description

The powertrain control module (PCM) electrically erasable programmable read only memory (EEPROM) contains data which is essential for operating the engine and transmission. The PCM continuously tests the integrity of this data.

Test Description

The number below refers to the step number on the diagnostic table.

  1. A DTC P0602 indicates the PCM is not programmed.

Step

Action

Yes

No

Schematic Reference: Engine Controls Schematics

1

Did you perform the Diagnostic System Check-Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

Is DTC P0602 set?

Go to Step 3

Go to Step 5

3

Program the PCM. Refer to Powertrain Control Module Programming .

Does DTC P0602 reset?

Go to Step 4

Go to Step 6

4
  1. Ensure that all tool connections are secure.
  2. Ensure that the programming equipment is operating correctly.
  3. Ensure that the correct software/calibration package is used.
  4. Attempt to program the PCM. Refer to Powertrain Control Module Programming .

Does DTC P0602 reset?

Go to Step 5

Go to Step 6

5

Replace the PCM. Refer to Powertrain Control Module Replacement .

Did you complete the replacement?

Go to Step 6

--

6
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.

Did the DTC fail this ignition

Go to Step 2

Go to Step 7

7

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

Go to Diagnostic Trouble Code (DTC) List

System OK