Grand Prix V6-191 3.1L VIN M SFI (1998)
Powertrain Control Module (PCM): Component Tests and General Diagnostics
Powertrain Control Module (PCM)
DIAGNOSIS
The approved procedure for diagnosing all powertrain control system faults is included in the Strategy Based Diagnostic Flow. See: Computers and
Control Systems/Testing and Inspection
The preliminary checks and the Powertrain On-board Diagnostic System Check must be performed to successfully diagnose and repair the powertrain
systems. See: Computers and Control Systems/Testing and Inspection
NOTES:
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To read and clear diagnostic trouble codes, use a scan tool. Use a scan tool to clear diagnostic trouble codes from the PCM memory.
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The Vehicle Identification Number (VIN) is programmed into the PCM. Do not exchange a PCM from another vehicle for testing or replacement.
When replacing the PCM, the VIN must also be programmed into the new PCM.
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Because the PCM can have a failure which may affect only one circuit, follow the diagnostic procedures in this section to determine which circuit
has a problem and where it is.
TROUBLESHOOTING
If a diagnostic chart indicates that the PCM connections or PCM is the cause of a problem and the PCM is replaced, but does not correct the problem,
one of the following may be the reason:
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There is a problem with the PCM terminal connections. The diagnostic chart will say PCM connections or PCM. The terminals may have to be
removed from the connector in order to check them properly.
^
EEPROM program is not correct for the application. Incorrect components may cause a malfunction and may or may not set a DTC.
^
The problem is intermittent. This means that the problem is not present at the time the system is being checked. In this case, refer to Symptoms
and make a careful physical inspection of all components and wiring associated with the affected system. See: Computers and Control
Systems/Testing and Inspection
^
There is a shorted solenoid, relay coil, or harness. Solenoids and relays are turned ON and OFF by the PCM using internal electronic switches
called drivers. Each driver is part of a group of seven called Output Driver Modules. A shorted solenoid, relay coil, or harness will not damage the
PCM but will cause the solenoid or relay to be inoperative. The J 34636 tester, or equivalent, provides a fast, accurate means of checking for a
shorted coil or a short to battery voltage.
