DTC P1135: Front O2 Sensor Heater Circuit Low: Condition

PCM supplies ground to heater to complete circuit. DTC is set if PCM detects voltage less than 5.8 volts when no ground is supplied to heater. Possible causes are:

• Front Heated O2 Sensor (FHO2S) heater malfunction.
• Open or short circuit in wiring.
• PCM malfunction.