DTC P0651 (2016 2017 2018 2019 2020 PGM-FI System (With Auto Idle Stop System))

DTC P0651 : Sensor Reference Voltage B Malfunction

NOTE: Before you troubleshoot, review the general troubleshooting information - Refer to: How to Troubleshoot the Brake Booster Pressure Monitoring System (2016 2017 2018 2019 2020), or How to Troubleshoot the Fuel and Emissions Systems(With Auto Idle Stop System) (2016), or How to Troubleshoot the Fuel and Emissions Systems, or How to Troubleshoot the A/T System (2014 2015) .

DTC Description	Confirmed DTC	Pending DTC	Freeze Frame
P0651 Sensor Reference Voltage B Malfunction

DTC (PGM-FI)

Problem verification

-1. Turn the vehicle to the ON mode.

- 2. Clear the DTC with the HDS.

- 3. Check for Pending or Confirmed DTCs with the HDS.

DTC Description	Confirmed DTC	Pending DTC	Freeze Frame
P0651 Sensor Reference Voltage B Malfunction

Is DTC P0651 indicated?

YES

The failure is duplicated. Go to step 2.

Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the PCM and these parts. If the freeze data/on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the freeze data/on-board snapshot.

APP sensor
Throttle body
Rocker arm oil pressure sensor

Determine possible failure area (VCC lines, others)

-1. Turn the vehicle to the OFF (LOCK) mode.

- 2. Disconnect the following connectors.

APP sensor 6P connector

Throttle body 6P connector

Rocker arm oil pressure sensor 3P connector

- 3. Turn the vehicle to the ON mode.

- 4. Clear the DTC with the HDS.

- 5. Check for Pending or Confirmed DTCs with the HDS.

DTC Description	Confirmed DTC	Pending DTC	Freeze Frame
P0651 Sensor Reference Voltage B Malfunction

Is DTC P0651 indicated?

YES

Go to step 4.

Go to step 3.

Shorted part check

-1. Check for Pending or Confirmed DTCs with the HDS while reconnecting these parts, one at a time:

APP sensor
Throttle body
Rocker arm oil pressure sensor

DTC Description	Confirmed DTC	Pending DTC	Freeze Frame
P0651 Sensor Reference Voltage B Malfunction

Is DTC P0651 indicated?

YES

Replace the part that caused the DTC when it was reconnected.

Check for poor connections or loose terminals at the PCM and the following parts, then go to step 1.

APP sensor
Throttle body
Rocker arm oil pressure sensor

Shorted wire check (VCC lines to power)

-1. Turn the vehicle to the OFF (LOCK) mode.

- 2. Jump the SCS line with the HDS.

- 3. Disconnect the following connectors.

PCM connector A (51P)

PCM connector B (51P)

- 4. Turn the vehicle to the ON mode.

- 5. Measure the voltage between these test points and body ground individually.

Test condition	Vehicle ON mode
	APP sensor 6P connector: disconnected
	Throttle body 6P connector: disconnected
	Rocker arm oil pressure sensor 3P connector: disconnected
	PCM connector A (51P): disconnected
	PCM connector B (51P): disconnected

Connector	Terminal
PCM connector A (51P) - Refer to: PCM Connector for Inputs and Outputs (2017 2018 2019 2020), or PCM Connector for Inputs and Outputs (2014 2015), or PCM Connector for Inputs and Outputs (2016)	No. 42
PCM connector B (51P) - Refer to: PCM Connector for Inputs and Outputs (2014 2015), or PCM Connector for Inputs and Outputs (2016), or PCM Connector for Inputs and Outputs (2017 2018 2019 2020)	No. 43 and No. 44

Is there about 5.2V or more?

YES

Repair a short to power in the VCC wire between the PCM (A42, B43, or B44) and each part that was disconnected in step 2.

Go to step 5.

Shorted wire check (VCC lines)

-1. Turn the vehicle to the OFF (LOCK) mode.

- 2. Check for continuity between these test points and body ground individually.

Test condition	Vehicle OFF (LOCK) mode
	APP sensor 6P connector: disconnected
	Throttle body 6P connector: disconnected
	Rocker arm oil pressure sensor 3P connector: disconnected
	PCM connector A (51P): disconnected
	PCM connector B (51P): disconnected

Connector	Terminal
PCM connector A (51P) - Refer to: PCM Connector for Inputs and Outputs (2014 2015), or PCM Connector for Inputs and Outputs (2016), or PCM Connector for Inputs and Outputs (2017 2018 2019 2020)	No. 42
PCM connector B (51P) - Refer to: PCM Connector for Inputs and Outputs (2014 2015), or PCM Connector for Inputs and Outputs (2016), or PCM Connector for Inputs and Outputs (2017 2018 2019 2020)	No. 43 and No. 44

Is there continuity?

YES

Repair a short in the VCC wire between the PCM (A42, B43, or B44) and each part that was disconnected in step 2.

The VCC wires are OK. Update the PCM if it does not have the latest software, or substitute a known-good PCM - Refer to: PCM Removal and Installation (2014 2015), or PCM Removal and Installation (2016) .