P1235

A : P1233, P1235 Fuel Pump Primary Circuit Failure

A1: AUDIBLE CHECK OF THE FUEL PUMP RELAY
1. LOCATE the fuel pump relay at the rear power distribution box.
2. Audibly CHECK the fuel pump relay for a clicking noise, while an assistant switches the ignition switch to the RUN position.

Is the fuel pump relay clicking?

Yes
Go to A2

No
Go to A4

A2: CHECK THE POSITIVE SUPPLY TO THE FUEL PUMP
1. Switch the ignition to the OFF position.
2. Disconnect the fuel pump electrical connector FP4.
3. Switch the ignition to the RUN position.
4. Measure the pulse width modulation voltage between the fuel pump electrical connector FP4 pin 1, (GO) and ground.

Is there a 1 second, 12 volts voltage signal after the ignition is switched on?

Yes
Go to A3

No
Go to A9

A3: CHECK THE GROUND SUPPLY TO THE FUEL PUMP
1. Switch the ignition to the OFF position.
2. Measure the resistance between the fuel pump electrical connector FP4 pin 3, (BR) and ground.

Is the resistance less than 0.5 Ohms?

Yes
INSTALL a new fuel pump. CLEAR DTC. TEST the system for normal operation.

No
Go to A11

A4: CHECK THE POSITIVE SUPPLY TO THE FUEL PUMP RELAY
1. REMOVE the fuel pump relay at the rear power distribution box.
2. Switch the ignition to the RUN position.
3. Measure the voltage at the fuel pump relay electrical connector pin 1.

Is the voltage less than 10.5 Volts?

Yes
Go to A5

No
Go to A13

A5: CHECK THE POSITIVE SUPPLY TO THE FUEL PUMP DIODE
1. Switch the ignition to the OFF position.
2. REMOVE the fuel pump diode at the rear distribution box.
3. Switch the ignition to the RUN position.
4. Measure the voltage between the fuel pump diode electrical connector CA61 pin G2, (GW) and GROUND.

Is the voltage less than 10.5 Volts?

Yes
Go to A6

No
INSTALL a new fuel pump diode. CLEAR DTC. TEST the system for normal operation.

A6: CHECK THE POSITIVE SUPPLY TO FUSE 4 AT THE PRIMARY JUNCTION BOX
1. Measure the voltage at the positive supply side of fuse 4 at the primary junction box.

Is the voltage less than 10.5 Volts?

Yes
TEST the voltage supply to the primary junction box from ignition switch.

No
Go to A7

A7: CHECK THE VOLTAGE SUPPLY BETWEEN THE INPUT SIDE OF INERTIA SWITCH AND OUTPUT SIDE OF FUSE 4 AT THE PRIMARY JUNCTION BOX
1. Switch the ignition to the OFF position.
2. Measure the resistance between fuse 4 at the primary junction box and the fuel shut-off inertia switch electrical connector CA4 pin X2, (GO).

Is the resistance less than 0.5 Ohms?

Yes
Go to A8

No
REPAIR the inertia fuel shut-off switch supply circuit. CLEAR DTC. TEST the system for normal operation.

A8: CHECK THE CONTINUITY BETWEEN THE OUTPUT SIDE OF INERTIA SWITCH AND THE POSITIVE SUPPLY TO FUEL PUMP DIODE
1. Measure the resistance between the inertia fuel shut-off switch electrical connector CA4 pin X3, (GW) the fuel pump diode electrical connector CA61 pin G2, (GW).

Is the resistance less than 0.5 Ohms?

Yes
INSTALL a new fuel inertia shut-off switch.

No
REPAIR the circuit between the inertia fuel shut-off switch electrical connector CA4 pin X3, (GW) and the fuel pump diode electrical connector CA6I pin G2, (GW). CLEAR DTC. TEST the system for normal operation.

A9: CHECK THE SWITCHABLE VOLTAGE SUPPLY TO THE FUEL PUMP RELAY
1. Switch the ignition to the OFF position.
2. REMOVE the fuel pump relay at the rear power distribution box.
3. Switch the ignition to the RUN position.
4. Measure the voltage at the fuel pump relay electrical connector pin 3 (R).

Is the voltage less than 10.5 Volts?

Yes
Go to A10

No
Go to A14

A10: CHECK THE FUEL PUMP RELAY SWITCHABLE VOLTAGE SUPPLY FUSE
1. Measure the voltage at the fuel pump relay switchable voltage supply fuse.

Is the voltage less than 10.5 Volts?

Yes
TEST the rear power distribution box power supply. CLEAR DTC. TEST the system for normal operation.

No
REPAIR the circuit between the rear power distribution box electrical connector CA61 pin X34, (R) and the fuel pump relay electrical connector pin 3, (R). CLEAR DTC. TEST the system for normal operation.

A11: CHECK THE CONTINUITY BETWEEN THE FUEL PUMP GROUND SUPPLY AND THE REAR ELECTRONIC MODULE
1. Measure the resistance between the fuel pump electrical connector FP4 pin 3, (BR) and the rear electronic module CA101 pin 12, (BR).

Is the resistance less than 0.5 Ohms?

Yes
Go to A12

No
REPAIR the circuit between the fuel pump electrical connector FP4 pin 3, (BR) and rear electronic module electrical connector CA101 pin 12, (BR). CLEAR DTC. TEST the system for normal operation.

A12: CHECK THE CONTINUITY BETWEEN THE REAR ELECTRONIC MODULE AND GROUND
1. Measure the resistance between the rear electronic module electrical connector CA101 pin 02, (B) and GROUND CA156, (B).

Is the resistance less than 0.5 Ohms?

Yes
Go to A16

No
REPAIR the circuit between the rear electronic module CA101 pin 02, (B) and GROUND CA156, (B). CLEAR DTC. TEST the system for normal operation.

A13: CHECK THE GROUND SUPPLY TO THE FUEL PUMP RELAY
1. Switch the ignition to the OFF position.
2. Measure the resistance between the fuel pump relay pin 2 (B) and GROUND CA116 (B).

Is the resistance less than 0.5 Ohms?

Yes
INSTALL a new fuel pump relay. CLEAR DTC. TEST the system for normal operation.

No
REPAIR the circuit between the fuel pump relay pin 2 (B) and GROUND CA116 (B). CLEAR DTC. TEST the system for normal operation.

A14: CHECK THE VOLTAGE OUTPUT AT THE FUEL PUMP RELAY
1. Switch the ignition to the OFF position.
2. INSTALL the fuel pump relay at the rear power distribution box.
3. Switch the ignition to the RUN position.
4. Measure the output voltage from the fuel pump relay electrical connector pin 5 at the rear electronic module electrical connector CA101 pin 01, (GO).

Is the voltage greater than 10.5 Volts?

Yes
Go to A15

No
INSTALL a new fuel pump relay. CLEAR DTC. TEST the system for normal operation.

A15: CHECK THE CONTINUITY BETWEEN THE REAR ELECTRONIC MODULE AND THE FUEL PUMP
1. Measure the resistance between the rear electronic module electrical connector CA101 pin 11, (GO) and fuel pump electrical connector FP4 pin 1, (GO).

Is the resistance less than 0.5 Ohms?

Yes
INSTALL a new rear electronics module. CLEAR DTC. TEST the system for normal operation.

No
REPAIR the circuit between the rear electronic module electrical connector CA101 pin 11, (GO) and the fuel pump electrical connector FP4 pin 1, (GO). CLEAR DTC. TEST the system for normal operation.

A16: CHECK THE CONTINUITY OF THE REAR ELECTRONIC MODULE SIGNAL SUPPLY CIRCUIT
1. Disconnect the powertrain control module electrical connector FH1.
2. Disconnect the rear electronic module electrical connector CA103.
3. Measure the resistance between the powertrain control module electrical connector FH1 pin 58, (WP) and the rear electronic module electrical connector CA103 pin 19, (WP).

Is the resistance less than 0.5 Ohms?

Yes
REPAIR the circuit between the powertrain control module electrical connector FH1 pin 58, (WP) and the rear electronic module electrical connector CA103 pin 19, (WP).

No
INSTALL a new rear electronics module. CLEAR DTC. TEST the system for normal operation.