The wiring for a 5.9 ZJ transmission can seem daunting, but understanding the function of each wire and connector is crucial for proper operation. This guide outlines the wiring connections for the three primary connectors associated with the transmission control module (TCM) in a 5.9 ZJ equipped with a 46RE transmission: an 8-prong gray connector, an 8-prong black connector, and a 26-prong black connector. This information is adapted from Stu Olsen’s Jeep site, modified slightly for 5.9 ZJ compatibility.
Decoding the 5.9 ZJ Transmission Connectors
The 8-Prong Gray Connector (Transmission Range Sensor – TRS)
This connector houses the Transmission Range Sensor (TRS) and communicates the gear selector position to the TCM.
- Pin 1 (Violet/White): TRS 1-2 Sense – Connects to TCM Pin 21 (T42 Sense), indicating the shifter is in the 1-2 position.
- Pin 2 (Violet): TRS 3 Sense – Connects to TCM Pin 9, indicating the shifter is in the 3 position.
- Pin 3 (White): Fused Ignition Switch Output (Run-Start) – Powers the TRS when the key is in the run or start position. Connects to the TJ PCM Connector 1, Pin A2.
- Pin 4 (Light Green/Black): TRS Overdrive Sense – Connects to TCM Pin 22 (T1 Sense), indicating the shifter is in overdrive.
- Pin 5: Not used.
- Pin 6 (Brown/Light Green): TRS Reverse Sense – Connects to TCM Pin 18 (Back Up Lamp Feed), indicating the shifter is in reverse.
- Pin 7 (Black/White): Park/Neutral Position Switch Sense – Grounds the Park/Neutral circuit when in park or neutral, enabling the starter. Connects to the TJ PCM Connector 1, Pin A6.
- Pin 8: Ground – Completes the Park/Neutral circuit. Connects to the TJ PCM Connector 1, Pin 31 or 32.
The 8-Prong Black Connector (Transmission Solenoids and Speed Sensors)
This connector manages the transmission solenoids and speed sensors, essential for shifting and TCM operation.
- Pin 1 (Red/Black): Input Speed Sensor Signal – Connects to TCM Pin 2, providing input speed data to the TCM.
- Pin 2 (Orange/White): Transmission Solenoid B – Connects to TCM Pin 13, controlling shifting.
- Pin 3 (White): Transmission Solenoid A – Connects to TCM Pin 12, controlling shifting.
- Pin 4 (Dark Blue/White): Transmission Solenoid C (Lockup) – Connects to TCM Pin 11, controlling torque converter lockup.
- Pin 5 (Violet/Light Green): Input Speed Sensor Ground – Connects to TCM Pin 1, completing the input speed sensor circuit.
- Pin 6 (Dark Blue/Black): Output Speed Sensor Ground – Connects to TCM Pin 3, completing the output speed sensor circuit.
- Pin 7 (Light Green/White): Output Speed Sensor Signal – Connects to TCM Pin 4, providing output speed data to the TCM.
- Pin 8: Not used.
The 26-Prong Black Connector (TCM)
This connector is the main interface for the TCM, connecting it to various sensors and the PCM.
- Pins 1-4: Correspond to the speed sensor signals and grounds from the 8-prong black connector.
- Pins 6-7 (CCD BUS): Not used.
- Pin 9 (Violet): TRS T3 Sense – Connects to the gray connector Pin 2 (TRS 3 Sense).
- Pins 11-13: Correspond to the transmission solenoid controls from the 8-prong black connector.
- Pin 16 (Brown/Yellow): Sensor Return (Sensor Ground) – Connects to the TJ PCM Connector 1, Pin A4, providing a common ground for various sensors.
- Pin 17 (Orange/Dark Blue): Throttle Position Sensor Signal – Connects to the TJ PCM Connector 1, Pin A23, providing throttle position data to the TCM.
- Pin 18 (Brown/Light Green): TRS Reverse Sense – Connects to the gray connector Pin 6 (TRS Reverse Sense).
- Pin 21 (Violet/White): TRS T42 Sense – Connects to the gray connector Pin 1 (TRS 1-2 Sense).
- Pin 22 (Light Green/Black): TRS T1 Sense – Connects to the gray connector Pin 4 (TRS Overdrive Sense).
- Pin 23 (White/Pink): Brake Switch Sense – Connects to the TJ PCM Connector 3, Pin C24, indicating brake application.
- Pin 24 (Black/Tan): Ground – Connects to the TJ PCM Connector 1, Pin A31 or A32, providing a ground for the TCM.
- Pin 25 (Pink): Fused B (+) – Connects directly to the battery positive terminal with a 15A inline fuse, providing constant power to the TCM.
- Pin 26 (Dark Blue/White): Fused Ignition Switch Input (Start-Run) – Connects to the TJ PCM Connector 1, Pin A2, providing power to the TCM in the run or start position.
Conclusion: Navigating the 5.9 ZJ’s Wiring Harness
This comprehensive guide provides a detailed breakdown of the 5.9 ZJ OBD2 wiring related to the transmission. Understanding these connections is vital for troubleshooting and ensuring the proper function of your transmission system. Remember, accurate wiring is essential for optimal performance and drivability.
