P1618-SENSOR REFERENCE VOLTAGE 1 CIRCUIT ERRATIC
For a complete wiring diagram Refer to Section 8W
- When Monitored:
With the ignition on.
- Set Condition:
The PCM detects an excessive voltage variation on the 5 volt supply circuit.
| Possible Causes |
| INTERMITTENT DTC |
| 5-VOLT SUPPLY CIRCUIT SHORTED TO VOLTAGE |
| 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND |
| 5-VOLT SUPPLY CIRCUIT OPEN OR HIGH RESISTANCE |
| ACCELERATOR PEDAL POSITION SENSOR |
| CAMSHAFT 2 POSITION SENSOR |
| THROTTLE POSITION SENSOR |
| CRANKSHAFT POSITION SENSOR |
| VEHICLE SPEED SENSOR (MTX ONLY) |
| POWERTRAIN CONTROL MODULE (PCM) |
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
Diagnostic Test
1. DTC IS ACTIVEStart the engine and allow it to reach normal operating temperature.
WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.
With the scan tool, select View DTCs.
Is the status Active for this DTC?
Yes
- Go to 2
No
- Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)
2. (F856) 5 VOLT SUPPLY CIRCUIT VOLTAGE
Turn the ignition off.
Disconnect the APP Sensor harness connector.
Turn the ignition on.
Measure the voltage of the (F856) 5 Volt Supply circuit.
Select the appropriate response from the list below:
Voltage more than 5.2 volts
- Repair the (F856) 5 Volt Supply circuit for a short to voltage.
- Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE)
Voltage between 4.8 and 5.2 volts
- Go to 3
Voltage below 4.8 volts
- Go to 4
3. ACCELERATOR PEDAL POSITION SENSOR
Turn the ignition off.
Connect the APP Sensor harness connector.
Disconnect the Camshaft 1/2 Position Sensor harness connector.
Turn the ignition on.
Measure the voltage of the (F856) 5 Volt Supply circuit in the Camshaft 1/2 Position Sensor harness connector.
Is the voltage below 4.8 volts?
Yes
- Replace the Accelerator Pedal Position Sensor.
- Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No
- Go to 11
4. CAMSHAFT 1/2 POSITION SENSOR
Turn the ignition off.
Disconnect the Camshaft 1/2 Position Sensor harness connector.
Turn the ignition on.
Measure the voltage of the (F855) 5 Volt Supply circuit in the APP Sensor harness connector.
Is the voltage above 4.8 volts?
Yes
- Replace the Camshaft 1/2 Position Sensor.
- Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No
- Go to 5
5. THROTTLE POSITION SENSOR
Turn the ignition off.
Disconnect the Throttle Body harness connector.
Turn the ignition on.
Measure the voltage of the (F855) 5 Volt Supply circuit.
Is the voltage above 4.8 volts?
Yes
- Replace the Throttle Body in accordance with the Service Information.
- Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No
- Go to 6
6. CRANKSHAFT POSITION SENSOR
Turn the ignition off.
Disconnect the Crankshaft Position Sensor harness connector.
Turn the ignition on.
Measure the voltage of the (F855) 5 Volt Supply circuit.
Is the voltage above 4.8 volts?
Yes
- Replace the Crankshaft Position Sensor.
- Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No
- Go to 7
7. VEHICLE EQUIPPED WITH MANUAL TRANSMISSION
NOTE: Only vehicles equipped with a manual transmission use a Vehicle Speed Sensor.
Is the vehicle equipped with a manual transmission?
Yes
- Go to 8
No
- Go to 9
8. VEHICLE SPEED SENSOR
NOTE: Only vehicles equipped with a manual transmission use a Vehicle Speed Sensor.
Turn the ignition off.
Disconnect the Vehicle Speed Sensor harness connector.
Turn the ignition on.
Measure the voltage of the (F856) 5 Volt Supply circuit.
Is the voltage above 4.8 volts?
Yes
- Replace the Vehicle Speed Sensor.
- Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No
- Go to 9
9. 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
NOTE: All sensors connected to the (F855) 5 volt supply circuit and the (F856) 5 volt supply circuit must be disconnected.
Turn the ignition off.
Disconnect the PCM harness connectors.
Measure the resistance between ground and the (F855) 5 Volt Supply circuit.
Measure the resistance between ground and the (F856) 5 Volt Supply circuit.
Is the resistance above 1000 ohms for both circuits?
Yes
- Go to 10
No
- Repair the 5 Volt Supply circuit for a short to ground.
- Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE)
10. 5-VOLT SUPPLY CIRCUIT OPEN OR HIGH RESISTANCE
NOTE: All sensors connected to the (F855) 5 volt supply circuit and the (F856) 5 volt supply circuit must be disconnected.
Turn the ignition off.
Measure the resistance of the (F855) 5 Volt Supply circuit between the Camshaft 1/2 Position Sensor harness connector and the PCM harness connector.
Measure the resistance of the (F855) 5 Volt Supply circuit between the Crankshaft Position Sensor harness connector and the PCM harness connector.
Measure the resistance of the (F855) 5 Volt Supply circuit between the Throttle Body harness connector and the PCM harness connector.
Measure the resistance of the (F856) 5 Volt Supply circuit between the Accelerator Pedal Position Sensor harness connector and the PCM harness connector.
If the vehicle is equipped with a manual transmission, measure the resistance of the (K856) 5 Volt Supply circuit between the Vehicle Speed Sensor harness connector and the PCM harness connector.
Is the resistance below 5.0 ohms for all of the circuits?
Yes
- Go to 11
No
- Repair the 5 Volt Supply circuit for an open circuit or high resistance.
- Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE)
11. POWERTRAIN CONTROL MODULE (PCM)
Inspect the (F855) 5 Volt Supply circuit between the Camshaft 1/2 Position Sensor harness connector and the PCM harness connector.
Inspect the (F855) 5 Volt Supply circuit between the Crankshaft Position Sensor harness connector and the PCM harness connector.
Inspect the (F855) 5 Volt Supply circuit between the Throttle Body harness connector and the PCM harness connector.
Inspect the (F856) 5 Volt Supply circuit between the Accelerator Pedal Position Sensor harness connector and the PCM harness connector.
If the vehicle is equipped with a manual transmission, inspect the (K856) 5 Volt Supply circuit between the Vehicle Speed Sensor harness connector and the PCM harness connector.
Inspect all PCM power and ground circuits.
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out or corroded terminals.
Refer to any Technical Service Bulletins that may apply.
Were any problems found?
Yes
- Repair as necessary.
- Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No
- Replace the PCM in accordance with the Service Information.
- Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - STANDARD PROCEDURE)