P2642 – Torque Management “B” Feedback Signal Range/Performance

P2642 Possible Causes

  • Faulty Engine Control Module (ECM)
  • Faulty Transmission Control Module (TCM)
  • Engine Control Module (ECM) software update
  • Transmission Control Module (TCM) software update
  • Engine Control Module (ECM) harness is open or shorted
  • Poor electrical connection in Engine Control Module (ECM) circuit

How to Fix Code P2642

Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

Illuminated engine light (or service engine soon warning light)

P2642 Meaning

To improve shift feel, the Transmission Control Module (TCM) may request that the Engine Control Module (ECM) reduce engine torque during shift events. When such a request is received, the ECM responds by retarding base ignition timing and notifying the TCM that the request was successful. If the ECM is unable to comply with the request, the ECM sends the TCM a message indicating the request failed.

The torque reduction request is sent to the ECM via a communication network called CAN (Controller Area Network). Two circuits are used to communicate CAN data between the ECM and TCM.

A fault in the CAN will not cause the ECM to set diagnostic trouble codes (DTCs). If a CAN fault occurs, other DTCs will be set before this code.

The ECM sets the OBDII code when the TCM receives a torque reduction failure message from the ECM.

P2643 – Low Torque Management Return Signal “B

P2643 Possible Causes

  • Faulty Engine Control Module (ECM)
  • Faulty Transmission Control Module (TCM)
  • Engine Control Module (ECM) software update
  • Transmission Control Module (TCM) software update
  • Engine Control Module (ECM) harness is open or shorted
  • Poor electrical connection in Engine Control Module (ECM) circuit

How to Fix Code P2643

Check the “Possible Causes” listed above. Visually inspect the wiring harness and related connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

Illuminated engine light (or service engine soon warning light)

P2643 Meaning

To improve shift feel, the Transmission Control Module (TCM) may request that the Engine Control Module (ECM) reduce engine torque during shift events. When such a request is received, the ECM responds by retarding base ignition timing and notifying the TCM that the request was successful. If the ECM is unable to comply with the request, the ECM sends the TCM a message indicating that the request failed.

The torque reduction request is sent to the ECM via a communication network called CAN (Controller Area Network). Two circuits are used to communicate CAN data between the ECM and TCM.

A fault in the CAN will not cause the ECM to set Diagnostic Trouble Codes (DTC). If a CAN fault occurs, other DTCs will be set before this code.

The ECM sets the OBDII code when the TCM receives a torque reduction failure message from the ECM.

P2644 – High Torque Management Return Signal “B

P2644 Possible Causes

  • Faulty Engine Control Module (ECM)
  • Faulty Transmission Control Module (TCM)
  • Engine Control Module (ECM) software update
  • Transmission Control Module (TCM) software update
  • Engine Control Module (ECM) harness is open or shorted
  • Poor electrical connection in Engine Control Module (ECM) circuit

How to Fix Code P2644

Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

Illuminated engine light (or service engine soon warning light)

P2644 Meaning

To improve shift feel, the Transmission Control Module (TCM) may request that the Engine Control Module (ECM) reduce engine torque during shift events. When such a request is received, the ECM responds by retarding base ignition timing and notifying the TCM that the request was successful. If the ECM is unable to comply with the request, the ECM sends the TCM a message indicating the request failed.

The torque reduction request is sent to the ECM via a communication network called CAN (Controller Area Network). Two circuits are used to communicate CAN data between the ECM and TCM.

A fault in the CAN will not cause the ECM to set diagnostic trouble codes (DTCs). If a CAN fault occurs, other DTCs will be set before this code.

The ECM sets the OBDII code when the TCM receives a torque reduction failure message from the ECM.

P2645 – Rocker Actuator Control Circuit ‘A’ / Bank 1 Open

P2645 Possible Causes

  • Low or overfilled engine oil
  • Incorrect engine oil type
  • Faulty rocker arm actuator ‘A’
  • Rocker arm actuator ‘A’ circuit is open or shorted
  • Poor electrical connection in rocker arm actuator ‘A’ circuit

How to Fix Code P2645

Check the “Possible Causes” listed above. Visually inspect the wiring harness and related connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

Illuminated engine light (or service engine soon warning light)

P2645 Meaning

The Engine Control Module (ECM) commands the rocker arm actuator to control the hydraulic oil circuit. Oil flows through the rocker arm actuator to the variable valve timing system to adjust engine valve timing. The Variable Valve Timing (VVT) system is used to improve engine performance, fuel economy, or emissions. The ECM monitors the rocker arm actuator circuit and sets the OBDII code when the rocker arm actuator ‘A’ circuit is outside factory specifications.

P2646 – Rocker Actuator System Performance ‘A’ / Row 1 Stuck

P2646 Possible Causes

  • Low or overfilled engine oil
  • Incorrect engine oil type
  • Faulty rocker arm actuator ‘A’
  • Rocker arm actuator ‘A’ circuit is open or shorted
  • Poor electrical connection in the rocker arm actuator ‘A’ circuit

How to Fix Code P2646

Check the “Possible Causes” listed above. Visually inspect the wiring harness and related connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

Illuminated engine light (or service engine soon warning light)

P2646 Meaning

The Engine Control Module (ECM) commands the rocker arm actuator to control the hydraulic oil circuit. Oil flows through the rocker arm actuator to the variable valve timing system to adjust the engine’s valve timing. The Variable Valve Timing (VVT) system is used to improve engine performance, fuel economy, or emissions. The ECM monitors the rocker arm actuator circuit and sets the OBDII code when the rocker arm actuator ‘A’ circuit is outside factory specifications.

P2647 – Rocker Actuator System “A” Stuck on Row 1

P2647 Possible Causes

  • Low or overfilled engine oil
  • Incorrect engine oil type
  • Faulty rocker arm actuator ‘A’
  • Rocker arm actuator ‘A’ circuit is open or shorted
  • Poor electrical connection in rocker arm actuator ‘A’ circuit

How to Fix Code P2647

Check the “Possible Causes” listed above. Visually inspect the wiring harness and related connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

Check engine light illuminated (or service engine soon warning light)

P2647 Meaning

The Engine Control Module (ECM) commands the rocker arm actuator to control the hydraulic oil circuit. Oil flows through the rocker arm actuator to the variable valve timing system to adjust engine valve timing. The Variable Valve Timing (VVT) system is used to improve engine performance, fuel economy, or emissions. The ECM monitors the rocker arm actuator circuit and sets the OBDII code when the rocker arm actuator ‘A’ circuit is outside factory specifications.

P2648 – Rocker Actuator ‘A’ Control Circuit, Bank 1 Low

P2648 Possible Causes

  • Low or overfilled engine oil
  • Incorrect engine oil type
  • Faulty rocker arm actuator ‘A’
  • Rocker arm actuator ‘A’ circuit open or shorted
  • Poor electrical connection in rocker arm actuator ‘A’ circuit

How to Fix Code P2648

Check the “Possible Causes” listed above. Visually inspect the wiring harness and related connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

Illuminated engine light (or service engine soon warning light)

P2648 Meaning

The Engine Control Module (ECM) commands the rocker arm actuator to control the hydraulic oil circuit. Oil flows through the rocker arm actuator to the variable valve timing system to adjust engine valve timing. The Variable Valve Timing (VVT) system is used to improve engine performance, fuel economy, or emissions. The ECM monitors the rocker arm actuator circuit and sets the OBDII code when the rocker arm actuator ‘A’ circuit is outside factory specifications.

P2649 – Rocker Actuator Control Circuit High ‘A’, Bank 1

P2649 Possible Causes

  • Low or overfilled engine oil
  • Incorrect engine oil type
  • Faulty rocker arm actuator ‘A’
  • Rocker arm actuator ‘A’ circuit open or shorted
  • Poor electrical connection in rocker arm actuator ‘A’ circuit

How to Fix Code P2649

Check the “Possible Causes” listed above. Visually inspect the wiring harness and related connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

Illuminated engine light (or service engine soon warning light)

P2649 Meaning

The Engine Control Module (ECM) commands the rocker arm actuator to control the hydraulic oil circuit. Oil flows through the rocker arm actuator to the variable valve timing system to adjust engine valve timing. The Variable Valve Timing (VVT) system is used to improve engine performance, fuel economy, or emissions. The ECM monitors the rocker arm actuator circuit and sets the OBDII code when the rocker arm actuator ‘A’ circuit is outside factory specifications.

P264A – Rocker Actuator Position Sensor Circuit ‘A’, Bank 1

P264A Possible Causes

  • Low or overfilled engine oil
  • Incorrect engine oil type
  • Faulty rocker arm actuator sensor ‘A’
  • Rocker arm actuator sensor ‘A’ circuit open or shorted
  • Poor electrical connection in rocker arm actuator sensor ‘A’ circuit

How to Fix Code P264A

Check the “possible causes” listed above. Visually inspect the related wiring harness and connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

Illuminated engine light (or service engine soon warning light)

P264A Meaning

The Engine Control Module (ECM) commands the rocker arm actuator to control the hydraulic oil circuit. Oil flows through the rocker arm actuator to the variable valve timing system to adjust engine valve timing. The Variable Valve Timing (VVT) system is used to improve engine performance, fuel economy, or emissions. The ECM monitors the rocker arm actuator position sensor ‘A’ and sets the OBDII code when the rocker arm actuator position sensor ‘A’ signal is outside factory specifications.

P264B – Rocker Actuator “A” Position Sensor Circuit Range/Performance, Bank 1

P264B Possible Causes

  • Low or overfilled engine oil
  • Incorrect engine oil type
  • Faulty rocker arm actuator sensor ‘A’
  • Rocker arm actuator sensor ‘A’ circuit open or shorted
  • Poor electrical connection in rocker arm actuator sensor ‘A’ circuit

How to Fix Code P264B

Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

Illuminated engine light (or service engine soon warning light)

P264B Meaning

The Engine Control Module (ECM) commands the rocker arm actuator to control the hydraulic oil circuit. Oil flows through the rocker arm actuator to the variable valve timing system to adjust engine valve timing. The Variable Valve Timing (VVT) system is used to improve engine performance, fuel economy, or emissions. The ECM monitors the rocker arm actuator position sensor ‘A’ and sets the OBDII code when the rocker arm actuator position sensor ‘A’ signal is outside factory specifications.