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Cell 22: Fuel Pump Controls
Circuit Description
When the key is turned ON, the PCM energizes the fuel pump relay which sends voltage to the lift pump. The lift pump remains ON during the glow plug cycle. If the engine is not started immediately after the glow plug cycle, the PCM shuts the fuel lift pump OFF and waits until the engine starts.
Diagnostic Aids
Possible long crank times or a poor performance problem will exist.
Test Description
The number(s) below refer to step number(s) on the Diagnostic Table.
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Checks for proper operation of the fuel pump.
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Checks the operation of the fuel pump by supplying 12 volts to the fuel pump control circuit.
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Check the battery feed circuit to the fuel pump relay.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 |
Important: Before clearing the DTCs, use the scan tool Capture Info to save the Freeze Frame and the Failure Records for reference. The controls module's data is deleted once the Clear Info function is used. Did you perform Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||
Does the fuel pump operate during the glow plug cycle? | -- | |||
Apply a 12 volt fused jumper to the fuel pump test terminal. Does the fuel pump operate? | -- | |||
Is the test lamp ON? | -- | |||
5 | Connect an J 35616-200 unpowered test lamp between the fuel pump relay battery feed circuit harness connector and the fuel pump relay ground at the harness connector. Is the test lamp ON? | -- | ||
6 |
Is the test lamp ON during glow plug cycle and then OFF? | -- | ||
7 |
Did you perform a repair? | -- | ||
8 |
Is the test lamp ON? | -- | ||
9 | With an J 35616-200 unpowered test lamp connected to B+ probe the fuel pump ground terminal (vehicle side) of the chassis harness fuel pump connector. Is the test lamp ON? | -- | ||
10 | Repair the open in the battery feed circuit to the fuel pump relay harness connector terminal. Refer to Wiring Repairs . Is the action complete? | -- | -- | |
11 | Repair the open in the fuel pump relay ground circuit. Refer to Wiring Repairs . Is the action complete? | -- | -- | |
12 |
Did you find a problem? | -- | ||
13 | Replace the fuel pump relay. Refer to Fuel Pump Relay Replacement . Is the action complete? | -- | -- | |
14 | Replace the fuel pump. Refer to Fuel Lift Pump Replacement . Is the action complete? | -- | -- | |
15 | Repair the open between the fuel pump test terminal and the fuel pump feed circuit at the fuel pump harness connector. Refer to Wiring Repairs. Is the action complete? | -- | -- | |
16 | Repair the open in the fuel pump harness ground circuit. Refer to Wiring Repairs . Is the action complete? | -- | -- | |
17 |
Important: The new PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming . Replace the PCM. Is the action complete? | -- | -- | |
18 | Operate the vehicle within the conditions the symptom was noted. Does the system operate properly? | -- |
