[ Model - ECLIPSE CROSS / Year - 2018 ]
2018 / ECLIPSE CROSS / EC - Workshop Manual
13 -FUEL > 13A-DIRECT INJECTION AND MULTIPOINT FUEL INJECTION (DI AND MPI) > TROUBLESHOOTING > DIAGNOSIS CODE PROCEDURES > CODE NO. P0038 OXYGEN SENSOR (REAR) HEATER CIRCUIT HIGH INPUT
Code No. P0038: Oxygen Sensor (rear) Heater Circuit High Input
 
 
 
 
OPERATION
  • Power is supplied to the heater power terminal of the oxygen sensor (rear) connector from the engine control relay.
  • The heater of the oxygen sensor (rear) connector is controlled by the power transistor in the engine-ECU connector terminal OHRL.
 
 
FUNCTION
  • The power supply to the oxygen sensor (rear) heater is controlled by the ON/OFF control of the power transistor in the engine-ECU.
  • Heating the oxygen sensor (rear) heater enables the oxygen sensor (rear) to provide good response even when the exhaust emission temperature is low.
 
 
TROUBLE JUDGEMENT
Check Conditions
  • More than 2 seconds have passed since the engine starting sequence was completed.
  • While the oxygen sensor (rear) heater is on.
  • Battery positive voltage is more than 11 V and is less than 16.5 V.
Judgement Criterion
  • The oxygen sensor (rear) heater current is more than 10.5 A for 2 seconds.
 
 
FAIL-SAFE AND BACKUP FUNCTION
  • None
 
 
PROBABLE CAUSES
  • Failed oxygen sensor (rear) heater
  • Short circuit in oxygen sensor (rear) heater circuit or loose connector contact
  • Failed engine-ECU
 
 
DIAGNOSIS PROCEDURE
STEP 1. Perform resistance measurement at oxygen sensor (rear) connector.
  • Disconnect connector, and measure at sensor side.
  • Resistance between terminal heater power supply line and engine-ECU OHRL line.
OK: 4.5 - 8.0 Ω (at 20°C)
Is the check result normal?
Go to Step 2.
Replace the oxygen sensor (rear).
 
STEP 2. Check of short to power supply in power supply line between engine control relay connector and oxygen sensor (rear) connector.
Is the check result normal?
Go to Step 3.
Repair the connector(s) or wiring harness.
 
STEP 3. Check of short to power supply in OHRL line between oxygen sensor (rear) connector and engine-ECU connector.
Is the check result normal?
Go to Step 4.
Repair the connector(s) or wiring harness.
 
STEP 4. M.U.T.-IIISE diagnosis code
  • Reconfirmation of diagnosis code.
Is the 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 ).