Fuel and air

P00A3 — Charge Air Cooler Temperature Sensor Circuit High, Bank 2

Severity: medium Drive with care, to a shop

What P00A3 means

The engine control unit reads a voltage from the charge air cooler temperature sensor on bank 2. The sensor is a thermistor, so cold air gives high resistance and high voltage. P00A3 sets when the signal stays above the expected range, which looks like an impossibly cold reading. An open circuit or a failed sensor is the most common reason.

Symptoms

  • Check Engine light on
  • Reduced power and sluggish acceleration
  • Worse fuel economy
  • Possible limp mode with limited boost
  • Rough running under load

Possible causes

  1. Failed charge air cooler temperature sensor
  2. Open circuit, corrosion or a loose connector in the wiring
  3. Signal wire shorted to voltage
  4. Missing 5V reference or a bad ground at the sensor
  5. Intercooler or hose problems (uncommon)
  6. Faulty PCM (rare)

How to diagnose

  1. Scan for codes and freeze frame data, and look for other temperature or boost related codes.
  2. Inspect the bank 2 sensor connector and harness for corrosion, chafing and bent pins.
  3. Compare the bank 2 reading with the bank 1 sensor and ambient temperature on a cold engine.
  4. Unplug the sensor and measure the 5V reference and ground with a multimeter.
  5. Measure sensor resistance and compare it to the manufacturer's spec at a known temperature.
  6. Test the signal wire for opens and shorts to voltage.
  7. If wiring and sensor are fine, inspect the intercooler and hoses, then consider the PCM.

Common fixes

  • Replace the charge air cooler temperature sensor
  • Repair the wiring or replace the damaged connector
  • Fix the 5V reference or ground circuit fault
  • Clean or replace the intercooler if airflow problems are confirmed
  • Replace or reflash the PCM as a last resort

Questions and answers

What does P00A3 mean?

It means the bank 2 charge air cooler temperature sensor circuit is reporting a high signal. The sensor or its wiring is the usual culprit.

Can I drive with P00A3?

Briefly, yes, but power may be limited. Get it diagnosed soon to avoid poor economy and extra engine stress.

How can I quickly find the cause?

Check the sensor connector, then compare its scan tool reading with the bank 1 sensor. A big difference points to the sensor or its wiring.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.