DTC P0237 (Flash Code 32) Turbocharger Boost Sensor Circuit Low (RZ4E-TC)

1. Engine control system check

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

2. Prioritized DTC check

1) Connect the scan tool.

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

3) Start the engine.

4) Observe the DTC information with a scan tool. Is DTC P1655 set at the same time?

Yes

Go to DTC P1655 diagnosis.

Refer to "51.Engine Control 1A.Troubleshooting(RZ4E-TC) DTC P1655 (Flash Code 59) Sensor Reference Voltage 4 Circuit".

No

=>Go to Boost pressure sensor signal voltage check.

3. Boost pressure sensor signal voltage check

1) Observe the Boost Pressure Sensor parameter on the scan tool. Is the Boost Pressure Sensor parameter less than or equal to the specified value?

Value: 0.1 V

Yes

=>Go to Boost pressure sensor 5 V reference voltage check.

No

Go to Intermittent conditions of engine.

Refer to "202.Engine 15D.Symptom(RZ4E-TC) intermittent conditions of engine".

4. Boost pressure sensor 5 V reference voltage check

1) Turn OFF the ignition switch.

2) Disconnect the boost pressure and CAC temperature sensor harness connector (E51).

3) Turn ON the ignition switch.

4) Measure the voltage between the boost pressure sensor 5 V reference circuit (pin 3 of E51) and the body ground with a DMM. Is the voltage more than or equal to the specified value?

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.).

Value: 4.5 V

Yes

=>Go to Boost pressure sensor signal voltage check using fused jumper wire.

No

=>Go to Inspection for open circuit in boost pressure sensor 5 V reference circuit.

5. Boost pressure sensor signal voltage check using fused jumper wire

1) Connect a fused jumper wire between the boost pressure sensor 5 V reference circuit and the signal circuit (pins 1 and 3 of E51).

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.).

2) Observe the Boost Pressure Sensor parameter on the scan tool. Is the Boost Pressure Sensor parameter more than or equal to the specified value?

Value: 4.5 V

Yes

=>Go to Boost pressure and CAC temperature sensor harness connector inspection.

No

=>Go to Inspection for open circuit and short circuit in boost pressure sensor signal circuit.

6. Inspection for open circuit in boost pressure sensor 5 V reference circuit

1) Inspect the boost pressure sensor 5 V reference circuit between the ECM (pin 14 of E4) and the boost pressure and CAC temperature sensor (pin 3 of E51) for an open circuit or high resistance. Is the result normal?

Note

  • The boost pressure sensor shares the 5 V reference circuit with other sensors. A malfunction in the 5 V reference circuit may set DTCs on sensors that share this circuit.

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.

7. Inspection for open circuit and short circuit in boost pressure sensor signal circuit

1) Inspect the boost pressure sensor signal circuit between the ECM (pin 10 of E4) and the boost pressure and CAC temperature sensor (pin 1 of E51) for the following. Is the result normal?

  • Open circuit
  • Short to ground
  • Short to the low reference circuit
  • High resistance

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.

8. Boost pressure and CAC temperature sensor harness connector inspection

1) Inspect for poor connections at the boost pressure and CAC temperature sensor harness connector (pins 1 and 3 of E51). 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 boost pressure and CAC temperature sensor.

Refer to "1.Engine 1Z.Engine Electrical Control(RZ4E-TC) boost pressure and CAC temperature sensor removal".

Refer to "1.Engine 1Z.Engine Electrical Control(RZ4E-TC) boost pressure and CAC temperature sensor installation".

=>Go to Repair verification.

No

Repair the connections as necessary.

=>Go to Repair verification.

9. ECM harness connector inspection

1) Inspect for poor connections at the ECM harness connector (pins 10 and 14 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.

10. 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.

11. 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.