Diagnostic Trouble Code (DTC) Information
Condition
The gear-shift position sensor signals provide the transmission control module (TCM) with data on the gear selector position. This is done by grounding a combination of signals A, B, C and PA inside the gear position sensor. Diagnostic trouble code (DTC) TCM-0039 is stored if the control module registers an unacceptable combination of A, B, C and PA for a period of approximately 10 seconds as shown below (depending on the transmission).
| AW 6 position gear selector assembly | ||||
|---|---|---|---|---|
| A | B | C | PA | |
| o | o | o | • | Diagnostic Trouble Code (DTC) |
| o | o | • | o | Diagnostic Trouble Code (DTC) |
| o | o | • | • | Diagnostic Trouble Code (DTC) |
| • | o | o | o | Diagnostic Trouble Code (DTC) |
| • | • | • | o | Diagnostic Trouble Code (DTC) |
| AW 7 position gear selector assembly | ||||
| A | B | C | PA | |
| o | o | o | • | Diagnostic Trouble Code (DTC) |
| o | o | • | o | Diagnostic Trouble Code (DTC) |
| • | • | • | • | Diagnostic Trouble Code (DTC) |
| • | o | o | o | Diagnostic Trouble Code (DTC) |
| GM4T65GT Geartronic | ||||
| A | B | C | PA | |
| o | o | o | • | Diagnostic Trouble Code (DTC) |
| o | o | • | o | Diagnostic Trouble Code (DTC) |
| o | o | • | • | Diagnostic Trouble Code (DTC) |
| • | o | o | o | Diagnostic Trouble Code (DTC) |
| • | o | • | o | Diagnostic Trouble Code (DTC) |
| • | • | • | o | Diagnostic Trouble Code (DTC) |
| • | o | • | • | Diagnostic Trouble Code (DTC) |
| GM4T65GT 7 position gear selector assembly | ||||
| A | B | C | PA | |
| o | o | o | • | Diagnostic Trouble Code (DTC) |
| • | o | o | o | Diagnostic Trouble Code (DTC) |
• = 0-2 V below battery voltage
o = ground
Substitute Value
- The control module "Limp Home" program has been initiated.
Possible Source
- Contact resistance in the terminals.
- Short-circuit to supply voltage or ground in the signal cable.
- Open-circuit in the signal cable.
- Incorrectly adjusted gear-shift position sensor.
- Defective gear-shift position sensor.
Fault symptom[s]
- General orange warning lamp lit.
- Malfunction indicator lamp (MIL) lit.
- No lock-up function.
- Harsh gear shifting.
- No shifting.
The gear-shift position sensor will malfunction if there is a short-circuit to supply voltage.
HINT: Harsh shifting - due to disabled line pressure solenoid STH control. This results in constant maximum line pressure and leads to harsher shifting and gear engagement.
HINT: No shifting -because the transmission control module (TCM) prevents activation of the solenoids. This stops gear-shifting.