DTC P0091 (Flash Code 247) Fuel Pressure Regulator Control Circuit Low (RZ4E-TC)

Note

  • If the FRP regulator low-side circuit is shorted to ground, this DTC will not be set. It will cause the engine to stall or to not start.

1. Engine control system check

Refer to "51.Engine Control 1A.Troubleshooting(RZ4E-TC) Diagnostic system check-engine controls".

2. Prioritized DTC check

1) Observe the DTC information with a scan tool. Is DTC P0092 set at the same time?

Yes

First diagnose DTC P0092.

Refer to "51.Engine Control 1A.Troubleshooting(RZ4E-TC) DTC P0092 (Flash Code 247) Fuel Pressure Regulator Control Circuit High".

=>Go to FRP regulator low-side voltage check.

No

=>Go to FRP regulator low-side voltage check.

3. FRP regulator low-side voltage check

1) Turn OFF the ignition switch.

2) Disconnect the FRP regulator harness connector (E52).

3) Connect a test lamp between the FRP regulator low-side circuit (pin 2 of E52) and the body ground.

Refer to "RHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "LHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).

4) Turn ON the ignition switch. Does the test lamp illuminate?

Yes

=>Go to Inspection for short to power supply in FRP regulator low-side circuit.

No

=>Go to FRP regulator high-side control voltage check.

4. FRP regulator high-side control voltage check

1) Turn OFF the ignition switch.

2) Connect a test lamp between the FRP regulator high-side circuit (pin 1 of E52) and the body ground.

Refer to "RHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "LHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).

3) Turn ON the ignition switch. Does the test lamp illuminate?

Yes

=>Go to FRP regulator low-side circuit inspection.

No

=>Go to Inspection for open circuit and short circuit in FRP regulator high-side circuit.

5. FRP regulator low-side circuit inspection

1) Turn OFF the ignition switch.

2) Connect a test lamp between the FRP regulator low-side circuit (pin 2 of E52) and the battery power supply.

Refer to "RHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "LHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).

3) Turn ON the ignition switch. Does the test lamp illuminate?

Yes

=>Go to Inspection for short circuit in FRP regulator low-side circuit.

No

=>Go to Inspection for open circuit in FRP regulator low-side circuit.

6. Inspection for short circuit in FRP regulator low-side circuit

1) Turn OFF the ignition switch with the test lamp connected.

2) Disconnect the ECM harness connector (E4). Does the test lamp illuminate?

Refer to "RHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "LHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Yes

=>Go to Inspection for short to ground in FRP regulator low-side circuit.

No

=>Go to Inspection for short circuit in FRP regulator circuit.

7. Inspection for short to power supply in FRP regulator low-side circuit

1) Inspect the low-side circuit between the ECM (pins 8 and 16 of E4) and the FRP regulator (pin 2 of E52) for a short to the battery power supply circuit or a short to the ignition power supply circuit. Is the result normal?

Note

  • The ECM may be damaged if the FRP regulator low-side circuit is shorted to the power supply.

Refer to "RHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "LHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Yes

=>Go to ECM replacement.

No

Repair the circuit as necessary.

=>Go to Repair verification.

8. Inspection for open circuit and short circuit in FRP regulator high-side circuit

1) Inspect the high-side circuit between the ECM (pins 24 and 32 of E4) and the FRP regulator (pin 1 of E52) for the following. Is the result normal?

  • Open circuit
  • High resistance
  • Short to ground

Refer to "RHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "LHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Yes

=>Go to ECM harness connector inspection.

No

Repair the circuit as necessary.

=>Go to Repair verification.

9. Inspection for open circuit in FRP regulator low-side circuit

1) Inspect the low-side circuit between the ECM (pins 8 and 16 of E4) and the FRP regulator (pin 2 of E52) for an open circuit or high resistance. Is the result normal?

Refer to "RHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "LHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Yes

=>Go to ECM harness connector inspection.

No

Repair the circuit as necessary.

=>Go to Repair verification.

10. Inspection for short to ground in FRP regulator low-side circuit

1) Inspect the low-side circuit between the ECM (pins 8 and 16 of E4) and the FRP regulator (pin 2 of E52) for a short to ground. Is the result normal?

Refer to "RHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "LHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Yes

=>Go to ECM replacement.

No

Repair the circuit as necessary.

=>Go to Repair verification.

11. Inspection for short circuit in FRP regulator circuit

1) Inspect the FRP regulator circuit (pins 1 and 2 of E52) for a short circuit. Is the result normal?

Refer to "RHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "LHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Yes

=>Go to FRP regulator harness connector inspection.

No

Repair the circuit as necessary.

=>Go to Repair verification.

12. FRP regulator harness connector inspection

1) Inspect for poor connections at the FRP regulator harness connector (pins 1 and 2 of E52). Is the connection status normal?

Refer to "RHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "LHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Yes

Replace the FRP regulator.

Note

  • Perform the learning of the fuel supply pump on the ECM after replacing the FRP regulator.

Refer to "1.Engine 1C.Fuel System(RZ4E-TC) FRP regulator removal".

Refer to "1.Engine 1C.Fuel System(RZ4E-TC) FRP regulator installation".

=>Go to Repair verification.

No

Repair the connections as necessary.

=>Go to Repair verification.

13. ECM harness connector inspection

1) Inspect for poor connections at the ECM harness connector (pins 8, 16, 24, and 32 of E4). Is the connection status normal?

Refer to "RHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "LHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Yes

=>Go to ECM replacement.

No

Repair the connections as necessary.

=>Go to Repair verification.

14. ECM replacement

Note

  • Perform programming after replacing the ECM.

Refer to "1.Engine 1Z.Engine Electrical Control(RZ4E-TC) ECM removal".

Refer to "1.Engine 1Z.Engine Electrical Control(RZ4E-TC) ECM installation".

Refer to "1.Engine 1Z.Engine Electrical Control(RZ4E-TC) ECM setting".

Procedure completion

=>Go to Repair verification.

15. Repair verification

1) Clear the DTC with a scan tool.

2) Turn OFF the ignition switch for 30 seconds or more.

3) Start the engine.

4) Operate the vehicle under the conditions for running the DTC.

5) Observe the DTC information with a scan tool.