Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Pinpoint Test E: Internal Module DTCS
- Normal Operation and Fault Conditions
The GSM runs periodic tests on itself. It sets a DTC if any of the results are outside of normal operating standards.
DTC Fault Trigger Conditions
DTC Description Fault Trigger Condition GSM P0605:00 Internal Control Module Read Only Memory (ROM) Error: No Sub Type Information This DTC indicates a ROM check sum error. GSM P0606:00 Control Module Processor: No Sub Type Information This DTC indicates the GSM experienced a reset without going through a proper sleep cycle. GSM P0607:00 Control Module Performance: No Sub Type Information This DTC indicates an early or delayed response of greater than 10 percent of its periodic rate. GSM P06B8:00 Internal Control Module Non-Volatile Random Access Memory (NVRAM) Error: No Sub Type Information This DTC indicates a RAM check sum error. GSM P164E:00 Internal Control Module Transmission Range Select Performance: No Sub Type Information This DTC indicates the GSM experienced a start up test failure, a program flow monitor failure, an IPC software failure, or a 5V_1_MONITOR failure. Possible Sources
- Discharged battery/charging system
- GSM calibration
- GSM
- E1 CHECK FOR DIAGNOSTIC TROUBLE CODES (DTCS)
- Ignition ON.
- Retrieve all CMDTCs from the GSM.
Is DTC P0562 or P0563 present in the GSM?
Yes RESOLVE those DTCs first. No GO to E2 - E2 PROGRAM THE GSM (GEAR SHIFT MODULE) WITH THE LATEST SOFTWARENOTE: If a GSM self-test is carried out, the driver door must be fully closed and locked. A false P166B DTC can set if the driver door is not fully closed or if it is unlocked during the self-test.
- Ignition ON.
- Clear all DTCs from the GSM.
- Reprogram the GSM with the latest software. REFER to: Module Programming .
- Using a diagnostic scan tool, carry out the GSM self-test.
Is DTC P0605, P0606, P0607, P06B8 and/or P164E present in the GSM?
Yes INSTALL a new GSM. REFER to: Gear Shift Module (GSM) . No The fault is not present at this time. It may have been caused by a module programming error.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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