| 1 |
Was "Engine and Emission Control System Check" performed? |
Go to Step 2. |
Go to ENGINE AND EMISSION CONTROL SYSTEM CHECK . |
| 2 |
A/F sensor heater circuit check
- Disconnect connector from A/F sensor (bank-2) with ignition switch turned OFF.
- Check for proper terminal connection to A/F sensor (bank- 2) connector.
- If connections are OK, measure circuit voltage between "Power supply circuit of A/F sensor (bank-2) heater" and vehicle body ground with ignition switch turned ON.
Is measured voltage 10 - 14 V? |
Go to Step 7. |
Go to Step 3. |
| 3 |
HO2S heater fuse check
- Check for "O2 HTR" fuse (1) blown.
Is "O2 HTR" fuse in good condition? |
Go to Step 6. |
Go to Step 4. |
| 4 |
HO2S heater relay power circuit check
- Disconnect connector from each A/F sensor and HO2S with ignition switch turned OFF.
- Remove HO2S heater relay (integration type relay) referring to ENGINE AND EMISSION CONTROL SYSTEM RELAY INSPECTION
and then check for proper terminal connection to relay connector.
- If connections are OK, check that HO2S heater relay circuit is as follows.
- Insulation resistance between "Power supply circuit of A/F sensor (bank-2) heater" and vehicle body ground is infinity.
- Insulation resistance between "Power supply circuit of HO2S heater relay" and vehicle body ground is infinity.
Is it in good condition? |
Go to Step 5. |
Repair or replace defective wire. |
| 5 |
A/F sensor and HO2S heater resistance check
- Check heater resistance of each A/F sensor and HO2S referring to AIR FUEL RATIO (A/F) SENSOR ON-VEHICLE INSPECTION
and HEATED OXYGEN SENSOR (HO2S-2) HEATER ON-VEHICLE INSPECTION
.
Are each A/F sensor heater and HO2S heater in good condition? |
Faulty HO2S heater relay. Check HO2S heater relay referring to ENGINE AND EMISSION CONTROL SYSTEM RELAY INSPECTION
. |
Replace defective sensor. |
| 6 |
HO2S heater relay power circuit check
- Disconnect connector from each A/F sensor and HO2S with ignition switch turned OFF.
- Remove HO2S heater relay (integration type relay) referring to ENGINE AND EMISSION CONTROL SYSTEM RELAY INSPECTION
and then check for proper terminal connection to relay connector.
- If connections are OK, check that HO2S heater relay circuit is as follows.
- Circuit voltage between "Power supply circuit of HO2S heater relay" and vehicle body ground is battery voltage with ignition switch turned ON.
- Circuit voltage between "Power supply circuit of HO2S heater relay coil" and vehicle body ground is battery voltage with ignition switch turned ON.
- Wiring harness resistance of each "Ground circuit of HO2S heater relay coil" and "power supply circuit of A/F sensor (bank-2) heater" is less than 1 Ω.
Is it in good condition? |
Faulty HO2S heater relay. Check HO2S heater relay referring to ENGINE AND EMISSION CONTROL SYSTEM RELAY INSPECTION
. |
Repair or replace defective wiring harness. |
| 7 |
A/F sensor heater circuit check
- Check that A/F sensor heater control circuit is as follows.
- Circuit voltage between "Control circuit of A/F sensor (bank-2) heater" and vehicle body ground is 0 V with ignition switch turned ON.
Is it good condition? |
Go to Step 8. |
Repair or replace defective wiring harness. |
| 8 |
A/F sensor heater circuit check
- Disconnect connectors from ECM and check for proper terminal connection to ECM connector.
- If connections are OK, check that A/F sensor heater circuit is as follows.
- Insulation resistance of wire harness is infinity between "Control circuit of A/F sensor (bank-2) heater" terminal and each other terminal at A/F sensor (bank-2) connector.
- Wiring harness resistance of "Control circuit of A/F sensor (bank-2) heater" and "Control ground circuit of A/F sensor (bank-2) heater" is less than 1 Ω.
- Insulation resistance between "Control circuit of A/F sensor (bank-2) heater" and "Control ground circuit of A/F sensor (bank-2) heater" is infinity.
Is measured resistance infinity? |
Go to Step 9. |
Repair or replace defective wiring harness. |
| 9 |
A/F sensor heater check
- Check heater resistance of A/F sensor (bank-2) referring to AIR FUEL RATIO (A/F) SENSOR ON-VEHICLE INSPECTION
.
Is A/F sensor heater in good condition? |
Substitute a known-good ECM and recheck. |
Replace A/F sensor (bank-2). |