DTC 313

FC. DTC 3-1-3
3-1-3 Gear position sensor signal faulty

Principle of operation

The gear position sensor incorporates the back-up light switch, the start inhibitor switch and the switches which inform the TCM of the gear which is selected. This is achieved by grounding a combination of leads A, B, C and PA internally within the sensor.

Fault description

DTC 3-1-3 means that an impermissible combination has been detected. The MIL lights, the TCM limp-home emergency program is activated and the transmission operates only in 4th gear with the gear selector lever in position D.

Troubleshooting consists of measuring resistances to determine if the fault is located in one or more of the leads, A, B, C and PA, in the sensor or in the TCM.

Note!
The gear position sensor cannot withstand a short-circuit to the supply.





Circuit description

The circuit consists of the TCM, the gear position sensor and the associated wiring and connectors.





1
Testing gear position sensor in test mode 2

Test all positions of gear position sensor in test mode 2. Displaying & Reading Trouble Codes

Note! Certain markets only:
The SHIFTLOCK RELEASE function must be used to change from position P to R, otherwise the brake light switch code will give misleading values.

If response codes are correct, fault is occurring only intermittently under particular conditions, making it considerably more difficult to locate.

Test drive car, shifting gear repeatedly to locate fault if possible.

If response code 2-4-3 is displayed, gear position sensor is faulty. OBD function cannot identify a permissible position. Check all positions of gear position sensor.





2
Measuring voltage of gear position sensor and leads

- Switch off ignition.
- Connect break-out box between TCM and wiring.
- Switch on ignition.

Connect voltmeter as per table.

- If readings are as shown in table, sensor and leads are OK.
In this case, DTC is due to intermittent fault. Return to Testing and Inspection. Diagnostic Procedures

- If all readings are close to battery voltage, ground connection is probably faulty.
- If readings in a single column are identical regardless of gear lever position, fault is probably in leads.
- If fault occurs in a specific gear position, sensor is faulty. Adjust sensor as per step 4. If fault persists, replace sensor.
Proceed to step 3 if results of preceding three steps are incorrect.





3
Measuring resistance of gear position sensor

- Switch off ignition.
- Open gear position sensor connector F.

Connect ohmmeter between pins 5, 6, 7, 8 in connector F on transmission and transmission housing (ground terminal).

- If readings are as shown in table, gear position sensor is OK.
Check leads for open-circuit and short-circuit to ground, also check ground terminal connection as described in Testing and Inspection, General Tests Component Tests and General Diagnostics then return to Testing and Inspection. Diagnostic Procedures

- If values differ from those in table, proceed to next step.

4
Checking/adjustment of gear position sensor

Adjust gear position sensor as per Transmission Position Switch/sensor. Adjustments to obtain correct response codes as per table in step 1.

Return to Testing and Inspection. Diagnostic Procedures