ASE G1 Auto Maintenance and Light RepairElectrical/Electronic SystemsHard
A vehicle's dashboard 'CHECK ENGINE' light is illuminated. A technician connects a scan tool and retrieves Diagnostic Trouble Code (DTC) P0135. What system does this code MOST directly indicate a fault in?
- AThe Anti-lock Braking System (ABS).
- BThe Evaporative Emission Control (EVAP) system.
- CThe Transmission Control System.
- DThe Oxygen Sensor Heater Circuit.
Show answer & explanationAnswer & explanation
Correct answer: D. The Oxygen Sensor Heater Circuit.
DTC P0135 specifically refers to a fault in the heater circuit of Oxygen Sensor 1, Bank 1. This is a common code indicating that the sensor's heater element is not functioning, which is crucial for the sensor to reach operating temperature quickly and provide accurate readings.
Why the other options are wrong
- A. ABS codes are usually C-codes (e.g., C0035).
- B. EVAP system codes typically start with P04xx (e.g., P0440).
- C. Transmission codes typically start with P07xx or P08xx.
DTC P0135
A Diagnostic Trouble Code indicating a malfunction in the heater circuit of the upstream (Bank 1, Sensor 1) oxygen sensor, preventing it from reaching operating temperature efficiently.
- Specific to O2 Sensor 1, Bank 1 heater circuit.
- Heater circuit ensures rapid sensor warm-up.
- Affects fuel mixture control and emissions.
Memory trick: P01xx: The 'O' is for Oxygen (and sometimes Fuel)