Pinpoint Test B: The Transmission Control Module (TCM) Does Not Respond to the Scan Tool

Communications Network

Pinpoint Tests

Pinpoint Test B: The Transmission Control Module (TCM) Does Not Respond To The Scan Tool

Refer to Wiring Diagram Set 14, Module Communications Network for schematic and connector information. Diagrams By Number

Refer to Wiring Diagram Set 29, Transmission Controls - 6 Speed for schematic and connector information. Diagrams By Number

Refer to Wiring Diagram Set 30, Transmission Controls - FNR5 for schematic and connector information. Diagrams By Number

Normal Operation

The Transmission Control Module (TCM) communicates with the scan tool through the High Speed Controller Area Network (HS-CAN). Circuits VDB04 (WH/BU) (HS-CAN +) and VDB05 (WH) (HS-CAN -) provide the network connection to the TCM. The FNR5 transaxle TCM and the 6-speed transaxle TCM both communicate on the HS-CAN. Voltage for the TCM is provided by circuits CBP18 (GY/OG), SBP07 (WH/RD) and SBB16 (VT/RD). Circuit GD120 (BK/GN) provides ground.

This pinpoint test is intended to diagnose the following:

- Fuse
- Wiring, terminals or connectors
- TCM

PINPOINT TEST B: THE TCM DOES NOT RESPOND TO THE SCAN TOOL

NOTICE: Use the correct probe adapter(s) when taking measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTE: Failure to disconnect the battery when instructed will result in false resistance readings. Refer to Battery.

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B1 CHECK THE TCM VOLTAGE SUPPLY CIRCUITS FOR AN OPEN

- Ignition OFF.
- Disconnect: TCM C2352a (FNR5 Transaxle).
- Disconnect: TCM C1533 (6-Speed Transaxle).
- Ignition ON.
- For FNR5 transaxles, measure the voltage between the TCM C2352a-3, circuit SBP23 (WH/RD), harness side and ground.

- For 6-speed transaxles, measure the voltage between the TCM C1533-1, circuit SBB16 (VT/RD), harness side and ground; and between the TCM C1533-11, circuit CBP18 (GY/OG), harness side and ground.

- Are the voltages greater than 10 volts?

Yes
GO to B2.

No
For FNR5 transaxles, VERIFY the Battery Junction Box (BJB) fuse 23 (10A) is OK.

For 6-speed transaxles, VERIFY the BJB fuse 16 (15A) or Smart Junction Box (SJB) fuse 26 (7.5A) is OK. If OK, REPAIR the circuit in question. CLEAR the DTCs. REPEAT the network test with the scan tool.

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B2 CHECK THE TCM GROUND CIRCUITS FOR AN OPEN

- Ignition OFF.
- Disconnect: Negative Battery Cable.
- For FNR5 transaxles, measure the resistance between the TCM C2352a-1, circuit GD120 (BK/GN), harness side and ground; and between the TCM C2352a-9, circuit GD120 (BK/GN), harness side and ground.

- For 6-speed transaxles, measure the resistance between TCM C1533-9, circuit GD120 (BK/GN), harness side and ground.

- Are the resistances less than 5 ohms?

Yes
For FNR5 transaxles, GO to B3 .

For 6-speed transaxles, GO to B4 .

No
REPAIR the circuit in question. CLEAR the DTCs. REPEAT the network test with the scan tool.

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B3 CHECK THE HS-CAN CIRCUITS BETWEEN THE FNR5 TRANSAXLE TCM AND THE DLC FOR AN OPEN

- Disconnect: TCM C2352b.
- Measure the resistance between the TCM C2352b-1, circuit VDB04 (WH/BU), harness side and the Data Link Connector (DLC) C251-6, circuit VDB04 (WH/BU), harness side.

- Measure the resistance between the TCM C2352b-13, circuit VDB05 (WH), harness side and the DLC C251-14, circuit VDB05 (WH), harness side.

- Measure the resistance between the TCM C1533-6, circuit VDB05 (WH), harness side and the DLC C251-14, circuit VDB05 (WH), harness side.

- Are the resistances less than 5 ohms?

Yes
CONNECT the negative battery cable. GO to B5.

No
REPAIR the circuit in question. CONNECT the negative battery cable. CLEAR the DTCs. REPEAT the network test with the scan tool.

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B5 CHECK FOR CORRECT TCM OPERATION

- Disconnect the TCM connector.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the TCM connector and make sure it seats correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?

Yes
INSTALL a new TCM. CLEAR the DTCs. REPEAT the network test with the scan tool.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the network test with the scan tool.

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