Fuel and air

P01AE — Alternative Fuel Tank Temperature Sensor Circuit Intermittent

Severity: low Safe to drive

What P01AE means

The PCM monitors the signal voltage from the temperature sensor in the alternative fuel tank, such as a gaseous or ethanol blend fuel supply. The signal normally changes smoothly as the fuel temperature changes. P01AE sets when that signal drops out, jumps around or doesn't make sense. The sensor or its wiring is the usual culprit.

Symptoms

  • Check Engine Light on
  • Erratic or wrong fuel temperature reading
  • Slightly worse fuel economy
  • Rough running on alternative fuel
  • Hard starting on alternative fuel (not always)

Possible causes

  1. Failed alternative fuel tank temperature sensor
  2. Corroded, loose or broken sensor connector
  3. Damaged or chafed wiring, short to ground or power
  4. Moisture or contamination in the connector
  5. PCM fault (rare)

How to diagnose

  1. Scan for codes and freeze frame data, record them, clear the code and see if it returns
  2. Watch fuel temperature in live data; it should change smoothly without jumps
  3. Inspect the sensor connector and harness for corrosion, moisture and chafing
  4. Wiggle the harness and connector with the engine running while watching the reading
  5. Check sensor reference voltage and ground using the factory wiring diagram
  6. Measure the sensor resistance and compare it to the spec at that temperature
  7. Test the wires to the PCM for opens and shorts
  8. If the sensor and wiring are good, test the PCM

Common fixes

  • Replace the fuel temperature sensor
  • Clean and repair the connector or replace it
  • Repair or replace the damaged wiring section
  • Update software or replace the PCM (rarely)

Questions and answers

What does P01AE mean?

The PCM detected an erratic or intermittent signal in the alternative fuel tank temperature sensor circuit. It points to a bad sensor or a wiring problem.

Can I drive with code P01AE?

Usually yes, particularly on the primary fuel. Performance on the alternative fuel may suffer, so don't put the repair off for long.

How do I fix P01AE?

Start by inspecting the sensor connector and wiring, then test the sensor with a multimeter. Repairing the wiring or replacing the sensor fixes most cases.

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.