DTC 112

DB. DTC 1-1-2
1-1-2 Short-circuit to supply in solenoid S1 circuit

Principle of operation

Solenoid S1 performs gearshifting in combination with solenoid S2. The solenoid operates when supplied with battery voltage from the TCM, which delivers an upshifting or downshifting signal depending on the speed of the car and the selected driving mode.

Fault description

A short-circuit has occurred at some point in the solenoid S1 circuit and the solenoid is energized permanently. The emergency limp-home program is activated and the transmission operates only in 4th gear. The MIL on the panel lights.
The fault is probably due to a short-circuit between leads. Troubleshooting should indicate if the short-circuit is in the wiring or TCM.





Circuit description

The circuit consists of the TCM, a number of connectors and solenoid S1 in the transmission.





1
Testing solenoid S1 in test mode 4

- Move gear selector lever to position P.

Test solenoid S1 in test mode 4 Use stethoscope to hear solenoid click more clearly. Displaying & Reading Trouble Codes

- If solenoid does not click, fault is permanent.
- If solenoid clicks, fault is occurring only intermittently under particular conditions, making it considerably more difficult to locate.





2
Measuring voltage with TCM disconnected

- Switch off ignition.
- Connect break-out box to wiring only.
- Switch on ignition.

Measure voltage across terminals # 8 (51) and # 12 (SG).

- If instrument indicates 0 V, wiring is OK. Proceed to next step.
- If instrument indicates battery voltage, short-circuit is between lead and other live lead. Proceed to step 3.

3
Measuring voltage with connector open

- Switch on ignition and connect break-out box as in previous step.
- Open connector E at transmission.

Repeat measurement across terminals # 8 (S1) and # 12 (SG).

- If instrument indicates battery voltage, fault is in wiring between connector and TCM. Component Tests and General Diagnostics

- if instrument indicates 0 V, fault is in harness between connector and solenoid S1. Replace harness.
Return to Testing and Inspection. Diagnostic Procedures






4
Measuring voltage with TCM in circuit
Switch off ignition.

- Connect break-out box between TCM and wiring.
- Select driving mode E and operate W button as per table.
- Move gear selector lever to position D.
- Switch on ignition.





Measure voltage across terminals # 8 (S1) and # 12 (SG).

5
Conclusions

- Steps 2 and 4 correct - intermittent fault
- Step 2 incorrect - fault in wiring
- Step 2 correct and step 3 incorrect - fault in TCM


Return to Testing and Inspection. Diagnostic Procedures