P-Code
SPN
FMI
P0656
96
31
P0657
650
5
P0658
650
4
P0659
650
3
P0686
1485
4
P0687
1485
3
P0691
1071
4
P0692
1071
3
P0693
1071
4
P0694
1071
3
P0695
1071
4
P0696
1071
3
P0698
3511
4
32
Diagnostic Troubleshooting Codes
Description
Fuel Level Output
Circuit Fault
Actuator Power Supply
Voltage A Circuit Open
Actuator Power Supply
Voltage A Circuit Low
Actuator Power Supply
Voltage A Circuit High
ECM/PCM Power Relay
Control Circuit Low
ECM/PCM Power Relay
Control Circuit High
Fan 1 Control Circuit
Low
Fan 1 Control Circuit
High
Fan 2 Control Circuit
Low
Fan 2 Control Circuit
Low
Fan 3 Control Circuit
Low
Fan 3 Control Circuit
Low
Sensor Reference
Voltage C Circuit Low
Possible Cause
Not applicable
Problem with the
actuator power
voltage circuit.
The actuator power
supply is lower than
expected.
The actuator power
supply is higher than
expected.
Problem with the
power control relay
circuit.
Problem with the
power control relay
circuit.
Not applicable
Not applicable
Not applicable
Not applicable
Not applicable
Not applicable
Problem with 5 V
sensor power supply.
Corrective Action
Not applicable
Check the relay coil and leads for
power and continuity.
Check the actuator relay coil and
leads for power and continuity.
Check the relay coil and leads for
power and continuity.
Check the battery and battery
charging alternator.
Check power control relay and
leads.
While the engine is running,
check for high system voltage at
the battery, alternator, and the
ECM power input pin.
Check power control relay and
leads.
Not applicable
Not applicable
Not applicable
Not applicable
Not applicable
Not applicable
Check the ECM leads.
Check for sensor shorts for
sensors using 5 V sensor power
supply by disconnecting all
sensors and then connecting
back one at a time.
Isolate a defective sensor. While
monitoring the sensor power
supply with a scan tool or
voltmeter, disconnect all sensors
powered from the sensor
reference voltage C power
supply. When the defective
sensor is plugged back in, the
voltage will fall.
Replace the ECM. Refer to
Section 5.4.
TP-6903 5/16a