Fuel Pump Electrical Circuit Diagnosis (LDD)
Diagnostic Instructions
Diagnostic Fault Information
Circuit
|
Short to Ground
|
Open/High Resistance
|
Short to Voltage
|
Signal Performance
|
B+
|
1
|
2
|
-
|
-
|
Control (fuel pump)
|
1
|
2
|
3
|
-
|
Control (fuel pump relay)
|
P0230 00
2
|
P0230 00
2
|
3
|
-
|
Ground (fuel pump relay)
|
-
|
P0230 00
2
|
-
|
-
|
Ground (fuel pump)
|
-
|
2
|
-
|
-
|
1. Open fuel pump fuse, cranks no start
2. The engine cranks but does not run
3. Fuel pump operates continuously, then discharged battery
|
|
| |
Circuit/System Description
When you turn ON the ignition switch, the engine control module
(ECM) energizes the fuel pump relay which powers the fuel pump ON.
The fuel pump remains ON as long as the engine is cranking or
running and the ECM receives ignition reference pulses. If there
are no ignition reference pulses, the ECM shuts the fuel pump OFF
within 2 s after the ignition was switched to the ON position or if
the engine stops.
Diagnostic Aids
The following conditions may cause the fuel pump fuse to
open:
| • |
The fuse F20UA is
faulty. |
| • |
There is an intermittent short
to ground in the fuel pump supply voltage circuit of the fuel
pump. |
| • |
The fuel pump has an
intermittent internal condition. |
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Fuel System Description
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Special Tools
EL 43244 Relay Puller Pliers
For equivalent regional tools, refer to
Special Tools .
Circuit/System Verification
With the ignition ON, engine OFF, command the fuel pump relay ON
and OFF several times using the scan tool output control function.
You should either hear or feel the relay click and the fuel pump
should turn ON and OFF with each command.
If the fuel pump operates continuously, test for a faulty KR23A
Fuel Pump Relay or a short to voltage in the G12 Fuel Pump supply
voltage circuit of the fuel pump.
Circuit/System Testing
| 1. |
Ignition OFF, the G12 Fuel
Pump should not be running. |
| ⇒ |
If the G12 Fuel Pump runs continuously, test the
KR23A Fuel Pump Relay switch supply circuit terminal 87 for a short
to voltage. If the circuit tests normal, replace the KR23A Fuel
Pump Relay. |
| 2. |
Ignition OFF, remove the KR23A
Fuel Pump Relay from the electrical centre with the EL
43244 Relay Puller Pliers . |
| 3. |
Verify a test lamp illuminates
between the KR23A Fuel Pump Relay ground circuit terminal 85 and
B+. |
| ⇒ |
If the test lamp does not illuminate, repair the
ground circuit for an open/high resistance. |
| 4. |
Ignition ON, test for 2-3 V
between the K20 Engine Control Module control circuit terminal 86
and ground. |
| ⇒ |
If less than the specified range, test the K20
Engine Control Module control circuit for a short to ground, or an
open/high resistance. If the circuit tests normal, replace the K20
Engine Control Module. |
| ⇒ |
If greater than the specified range, test the K20
Engine Control Module control circuit for a short to voltage. If
the circuit/connections test normal, replace the K20 Engine Control
Module. |
| 5. |
Command the G12 Fuel Pump ON
with a scan tool. The DMM should transition from 2-3 V when
commanded OFF to greater than 10 V when commanded ON. |
| ⇒ |
If the circuit voltage does not correspond to the
specified values, replace the K20 Engine Control Module. |
| 6. |
Verify a test lamp illuminates
between the KR23A Fuel Pump Relay switch B+ voltage circuit
terminal 30 and ground. |
| ⇒ |
If the test lamp does not illuminate, repair the
KR23A Fuel Pump Relay switch B+ voltage circuit for a short to
ground or an open/high resistance. |
| 7. |
Install a 15 A fused jumper
wire between the KR23A Fuel Pump Relay switch B+ voltage circuit
terminal 30 and the KR23A Fuel Pump Relay switch supply circuit
terminal 87. The G12 Fuel Pump should turn ON. |
| ⇒ |
If the fuel pump does not turn ON, test the KR23A
Fuel Pump Relay switch supply circuit and the G12 Fuel Pump motor
ground circuit for an open/high resistance. If the circuits test
normal, replace the G12 Fuel Pump. |
| 8. |
If all circuits test normal,
test or replace the KR23A Fuel Pump Relay. |
Component Testing
Relay Test
| 1. |
Ignition OFF, remove the KR23A
Fuel Pump Relay from the electrical centre with the EL
43244 Relay Puller Pliers . |
| 2. |
Test for 70-110 Ω
between terminals 85 and 86. |
| ⇒ |
If not within the specified range, replace the
KR23A Fuel Pump Relay. |
| 3. |
Test for infinite resistance
between the following terminals: |
| ⇒ |
If not the specified value, replace the KR23A Fuel
Pump Relay. |
| 4. |
Install a 20 A fused jumper
wire between KR23A Fuel Pump Relay terminal 85 and 12 V. Install a
jumper wire between KR23A Fuel Pump Relay terminal 86 and ground.
Test for less than 2 Ω between terminals 30 and 87.
|
| ⇒ |
If greater than the specified range, replace the
KR23A Fuel Pump Relay. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
|
