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 (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 under-hood fuse/relay box, and the ECM.■
  1. Turn the ignition switch to LOCK (0).
  1. Check the No. 13 LAF (A/F SENSOR) (15 A) fuse in the under-hood fuse/relay box.
Is the fuse OK?
YES -
Go to Step 7 .
NO -
Go to Step 18 .
  1. Test the PGM-FI subrelay in the under-hood fuse/relay box.
Is the PGM-FI subrelay OK?
YES -
Go to Step 8 .
NO -
Replace the under-hood fuse/relay box, then go to Step 22 .
  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 1.9−2.7 Ω at room temperature?
YES -
Go to Step 10 .
NO -
Go to Step 21 .