Code No. P0058: Left Bank Oxygen Sensor (rear) Heater Circuit High Input






OPERATION



  • Power is supplied to the heater power terminal (terminal No. 1) of the left bank oxygen sensor (rear) connector from the engine control relay (terminal No. 2).
  • The heater (terminal No. 3) of the left bank oxygen sensor (rear) connector is controlled by the power transistor in the engine-ECU (terminal No. 35).

FUNCTION



  • The power supply to the left bank oxygen sensor (rear) heater is controlled by the ON/OFF control of the power transistor in the engine-ECU.
  • Heating the left bank oxygen sensor (rear) heater enables the left bank oxygen sensor (rear) to provide good response even when the exhaust emission temperature is low.

TROUBLE JUDGMENT


Check Conditions
  • More than 2 seconds have passed since the engine starting sequence was completed.
  • While the left bank oxygen sensor (rear) heater is on.
  • Battery positive voltage is 11 - 16.5 V.
Judgement Criterion
  • The left bank oxygen sensor (rear) heater current has continued to be higher than 10.5 A for 2 seconds.

PROBABLE CAUSES



  • Failed left bank oxygen sensor (rear) heater
  • Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. Perform resistance measurement at B-41 left bank oxygen sensor (rear) connector.

  • Disconnect connector, and measure at sensor side.
  • Resistance between terminal No. 1 and No. 3.
OK: 11 - 18 Ω (at 20°C)

Q. Is the check result normal?
Go to Step 2 .
Replace the left bank oxygen sensor (rear).

STEP 2. M.U.T.-III diagnosis code

  • Reconfirmation of diagnosis code.

Q. Is diagnosis code set?
Replace the engine-ECU.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).