DTC Troubleshooting: P0135 (41)
DTC P0135:
 A/F Sensor (Sensor 1) Heater Circuit Malfunction
NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information.
  1. Turn the ignition switch to ON (II).
  1. Clear the DTC with the HDS.
  1. Start the engine. Hold the engine speed at 3,000 rpm (min −1 ) without load (A/T in P or N, M/T in neutral) until the radiator fan comes on, then let it idle.
  1. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0135 indicated?
YES -
Go to Step 5 .
NO -
Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the A/F sensor (Sensor 1), the PGM-FI subrelay, and the ECM/PCM.■
  1. Turn the ignition switch to LOCK (0).
  1. Check the No. 14 FI SUB (15 A) fuse in the under-hood fuse/relay box.
Is the fuse OK?
YES -
Go to Step 7 .
NO -
Go to Step 19 .
Is the relay OK?
YES -
Go to Step 9 .
NO -
Replace the PGM-FI subrelay, then go to Step 23 .
  1. Disconnect the A/F sensor (Sensor 1) 4P connector.
  1. At the sensor side, measure the resistance between A/F sensor (Sensor 1) 4P connector terminals No. 3 and No. 4.
Is there 2.0−2.7 Ω at room temperature?
YES -
Go to Step 11 .
NO -
Go to Step 22 .
  1. At the sensor side, check for continuity between A/F sensor (Sensor 1) 4P connector terminals No. 1 and No. 3, and between terminals No. 1 and No. 4 individually.
Is there continuity?
YES -
Go to Step 22 .
NO -
Go to Step 12 .
  1. Jump the SCS line with the HDS.
  1. Disconnect ECM/PCM connector C (44P).
  1. Check for continuity between ECM/PCM connector terminal C9 and body ground.
Is there continuity?
YES -
Repair short in the wire between the ECM/PCM (C9) and the A/F sensor (Sensor 1), then go to Step 23 .
NO -
Go to Step 15 .
  1. Check for continuity between A/F sensor (Sensor 1) 4P connector terminal No. 3 and ECM/PCM connector terminal C9.
Is there continuity?
YES -
Go to Step 16 .
NO -
Repair open in the wire between the ECM/PCM (C9) and the A/F sensor (Sensor 1), then go to Step 23 .
  1. Check for continuity between A/F sensor (Sensor 1) 4P connector terminal No. 4 and PGM-FI subrelay 4P connector terminal No. 2.
Is there continuity?
YES -
Go to Step 17 .
NO -
Repair open in the wire between the A/F sensor (Sensor 1) and the PGM-FI subrelay, then go to Step 23 .
  1. Disconnect ECM/PCM connector A (44P).
  1. Check for continuity between PGM-FI subrelay 4P connector terminal No. 3 and ECM/PCM connector terminal A21.
Is there continuity?
YES -
Go to Step 29 .
NO -
Repair open in the wire between the ECM/PCM (A21) and the PGM-FI subrelay, then go to Step 23 .
  1. Remove the PGM-FI subrelay (A) from the under-hood fuse/relay box.
  1. Disconnect the A/F sensor (Sensor 1) 4P connector.
  1. Check for continuity between A/F sensor (Sensor 1) 4P connector terminal No. 4 and body ground.
Is there continuity?
YES -
Repair short in the wire between the PGM-FI subrelay and the A/F sensor (Sensor 1). Also replace the No. 14 FI SUB (15 A) fuse, then go to Step 23 .
NO -
  1. Reconnect all connectors.
  1. Turn the ignition switch to ON (II).
  1. Reset the ECM/PCM with the HDS.
  1. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0135 indicated?
YES -
Check for poor connections or loose terminals at the A/F sensor (Sensor 1), the PGM-FI subrelay, and the ECM/PCM, then go to Step 1 .
NO -
Go to Step 28 .
  1. Monitor the OBD STATUS for DTC P0135 in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES -
Troubleshooting is complete. If any other Temporary DTCs or DTCs were indicated in Step 27 , go to the indicated DTC's troubleshooting.■
NO -
If the screen indicates FAILED, check for poor connections or loose terminals at the A/F sensor (Sensor 1), the PGM-FI subrelay, and the ECM/PCM, then go to Step 1 . If the screen indicates NOT COMPLETED, keep idling until a result comes on.
  1. Reconnect all connectors.
  1. Start the engine, and let it idle.
  1. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0135 indicated?
YES -
Check for poor connections or loose terminals at the A/F sensor (Sensor 1), the PGM-FI subrelay, and the ECM/PCM. If the ECM/PCM was updated, substitute a known-good ECM/PCM, then go to Step 31 . If the ECM/PCM was substituted, go to Step 1 .
NO -
Go to Step 33 .
  1. Monitor the OBD STATUS for DTC P0135 in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES -
If the ECM/PCM was updated, troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM. If any other Temporary DTCs or DTCs were indicated in Step 32 , go to the indicated DTC's troubleshooting.■
NO -
If the screen indicates FAILED, check for poor connections or loose terminals at the A/F sensor (Sensor 1), the PGM-FI subrelay, and the ECM/PCM. If the ECM/PCM was updated, substitute a known-good ECM/PCM, then go to Step 31 . If the ECM/PCM was substituted, go to Step 1 . If the screen indicates NOT COMPLETED, keep idling until a result comes on.