Fuel Pump Electrical Circuit Diagnosis (LUJ)
Diagnostic Instructions
Diagnostic Fault Information
Circuit
|
Short to Ground
|
Open/High Resistance
|
Short to Voltage
|
Signal Performance
|
Fuel Pump High Signal
|
P0231
|
P023F
|
P0232
|
P023F, P2635
|
Fuel Pump Low Signal
|
-
|
P023F
|
-
|
P023F, P2635
|
|
| |
Circuit/System Description
The engine control module (ECM) supplies voltage to the fuel
pump control module when the ECM detects that the ignition is on.
The voltage from the ECM to the fuel pump control module remains
active for two seconds, unless the engine is in crank or run. While
this voltage is being received, the fuel pump control module closes
the ground switch of the fuel pump and also supplies a varying
voltage to the fuel tank pump module in order to maintain the
desired fuel rail pressure.
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Fuel System Description
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Ignition ON, command the fuel pump ON and OFF using the scan
tool ECM output control. The fuel pump should turn on and off.
Circuit/System Testing
| 1. |
Ignition OFF, disconnect the
harness connector at the G12 fuel pump. |
| 2. |
Connect a test lamp between
the control circuit terminal 1 and ground. |
| 3. |
Ignition ON, command the G12
fuel pump ON and OFF using a scan tool ECM fuel pump output
control. The test lamp should turn ON and OFF, as commanded.
|
| ⇒ |
If the test lamp is always ON, test the control
circuit for a short to voltage. If the circuit tests normal,
replace the K27 fuel pump control module. |
| ⇒ |
If the test lamp is always OFF, test the control
circuit for a short to ground or an open/high resistance. If the
circuit tests normal, replace the K27 fuel pump control
module. |
| 4. |
Ignition OFF, connect a test
lamp between the control circuit terminal 1 and the low reference
circuit terminal 2. |
| 5. |
Ignition ON, command the G12
fuel pump ON using a scan tool. The test lamp should
illuminate. |
| ⇒ |
If the test lamp does not illuminate, test the low
reference circuit terminal 1 for a short to voltage or an open/high
resistance. If the circuit tests normal, replace the K27 fuel pump
control module. |
| 6. |
If all circuits test normal,
replace the G12 fuel pump. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
|
