DTC P0138, P0158 (20 6-Speed A/T)
DTC P0138 : Rear Secondary Heated Oxygen Sensor (Secondary HO2S (Bank 1, Sensor 2)) Circuit High Voltage
DTC P0158 : Front Secondary Heated Oxygen Sensor (Secondary HO2S (Bank 2, Sensor 2)) Circuit High Voltage
NOTE:
- Before you troubleshoot, review the general troubleshooting information - Refer to: How to Troubleshoot the Fuel and Emissions Systems
- Information marked with an asterisk (*) applies to the front bank (Bank 2).
| DTC Description | Confirmed DTC | Pending DTC |
|---|---|---|
| P0138 Rear Secondary Heated Oxygen Sensor (Secondary HO2S (Bank 1, Sensor 2)) Circuit High Voltage | ||
| P0158 Front Secondary Heated Oxygen Sensor (Secondary HO2S (Bank 2, Sensor 2)) Circuit High Voltage |
DTC (PGM-FI)
- Problem verification
-1. Turn the vehicle to the ON mode.
- 2. Clear the DTC with the HDS.
- 3. Turn the vehicle to the OFF (LOCK) mode.
- 4. Start the engine.
- 5. Hold the engine speed at 3, 000 rpm without load (in P or N) until the radiator fan comes on, then let it idle.
- 6. Check for Pending or Confirmed DTCs with the HDS.
DTC Description Confirmed DTC Pending DTC P0138 Rear Secondary HO2S (Bank 1, Sensor 2) Circuit High Voltage P0158 Front Secondary HO2S (Bank 2, Sensor 2) Circuit High Voltage Is DTC P0138 and/or P0158 * indicated?
YES
The failure is duplicated. Go to step 2.
NO
Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at secondary HO2S (Sensor 2) and the PCM. If the on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the on-board snapshot - Refer to: How to Troubleshoot the Fuel and Emissions Systems
- Determine possible failure area (open circuit, short circuit)
-1. Turn the vehicle to the OFF (LOCK) mode.
- 2. Disconnect the following connector.
Secondary HO2S (Sensor 2) 4P connector - 3. Connect terminals A and B with a jumper wire.
Rear bank (Bank1)
Terminal A Rear secondary HO2S (Bank 1, Sensor 2) 4P connector (female terminals) No. 1: Terminal B Rear secondary HO2S (Bank 1, Sensor 2) 4P connector (female terminals) No. 2: Front bank (Bank2)
Terminal A Front secondary HO2S (Bank 2, Sensor 2) 4P connector (male terminals) No. 1: Terminal B Front secondary HO2S (Bank 2, Sensor 2) 4P connector (male terminals) No. 2: - 4. Turn the vehicle to the ON mode.
- 5. Check the parameter (s) below with the HDS.
Signal Threshold Current conditions Values Unit Values Unit HO2S B1 S2 More than 1.42 V HO2S B2 S2 * More than 1.42 V Do the current condition (s) match the threshold?
YES
Go to step 3.
NO
Go to step 5.
- Open wire check (SO2SGB1 (SO2SGB2) * line):
- 1.Turn the vehicle to the OFF (LOCK) mode.
- 2. Remove the jumper wire from the secondary HO2S (Sensor 2) 4P connector.
- 3. Connect terminals A and B with a jumper wire.
Rear bank (Bank 1):
Terminal A Rear secondary HO2S (Bank 1, Sensor 2) 4P connector (female terminals) No. 2: Terminal B Body ground Front bank (Bank 2):
Terminal A Front secondary HO2S (Bank 2, Sensor 2) 4P connector (male terminals) No. 1: Terminal B Body ground - 4. Turn the vehicle to the ON mode.
- 5. Check the parameter (s) below with the HDS.
Signal Threshold Current conditions Values Unit Values Unit HO2S B1 S2 More than 1.42 V HO2S B2 S2 * More than 1.42 V Do the current condition (s) match the threshold?
YES
Go to step 4.
NO
Repair an open in the SO2SGB1 (SO2SGB2) * wire between the PCM (C39 (C40) *) and secondary HO2S (Sensor 2).
- Open wire check (SO2B1 (SO2B2) * line):
- 1.Turn the vehicle to the OFF (LOCK) mode.
- 2. Jump the SCS line with the HDS, and wait more than 1 minute.
- 3. Disconnect the following connector.
PCM connector C (51P) - 4. Measure the resistance between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode
Rear secondary HO2S (Bank 1, Sensor 2) 4P connector: disconnected Rear secondary HO2S (Bank 1, Sensor 2) 4P connector No. 2: jumped to body ground Front secondary HO2S (Bank 2, Sensor 2) 4P connector: disconnected * Front secondary HO2S (Bank 2, Sensor 2) 4P connector No. 1: jumped to body ground * PCM connector C (51P): disconnected Test point 1
PCM connector C (51P) No. 30 - Refer to:
PCM Connector for Inputs and Outputs (6-Speed A/T) (2016 2017 2018 2019 2020) .PCM connector C (51P) No. 31 * - Refer to:
PCM Connector for Inputs and Outputs (6-Speed A/T) (2016 2017 2018 2019 2020)Test point 2 Body ground Is there 1Ω or less?
YES
The SO2B1 (SO2B2) * wire is OK. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM - Refer to: PCM Removal and Installation (6-Speed A/T), (9-Speed A/T 2016 2017 2018) , then recheck. If DTC P0138 and/or P0158 * goes away and the PCM was substituted, replace the original PCM - Refer to: PCM Removal and Installation (6-Speed A/T), (9-Speed A/T 2016 2017 2018) .
NO
Repair an open in the SO2B1 (SO2B2) * wire between the PCM (C30 (C31) *) and secondary HO2S (Sensor 2).
- Shorted wire check (SO2SGB1 (SO2SGB2) * line to power):
- 1.Turn the vehicle to the OFF (LOCK) mode.
- 2. Remove the jumper wire from the secondary HO2S (Sensor 2) 4P connector.
- 3. Jump the SCS line with the HDS, and wait more than 1 minute.
- 4. Disconnect the following connector.
PCM connector C (51P) - 5. Turn the vehicle to the ON mode.
- 6. Measure the voltage between test points 1 and 2.
Test condition Vehicle ON mode
Rear Secondary HO2S (Bank 1, Sensor 2) 4P connector: disconnected Front secondary HO2S (Bank 2, Sensor 2) 4P connector *: disconnected PCM connector C (51P): disconnected Test point 1 Rear Secondary HO2S (Bank 1, Sensor 2) 4P connector (female terminals) No. 2: Front Secondary HO2S (Bank 2, Sensor 2) 4P connector (male terminals) No. 1:
Test point 2 Body ground Is there about 5 V or more?
YES
Repair a short to power in the SO2SGB1 (SO2SGB2) * wire between the PCM (C30 (C31) *) and secondary HO2S (Sensor 2).
NO
The SO2SGB1 (SO2SGB2) * wire is OK. Replace secondary HO2S (Sensor 2) .