Electrical and sensors

P00DB — Ambient Air Temperature Sensor Circuit B Low

Severity: low Safe to drive

What P00DB means

The control module monitors the voltage in circuit B of the ambient air temperature sensor. The sensor is a thermistor whose resistance changes with temperature. P00DB sets when the signal voltage stays below the expected range. This usually points to a signal wire shorted to ground or a failed sensor.

Symptoms

  • Check Engine light is on
  • Wrong or erratic outside temperature display
  • Climate control behaves incorrectly
  • Minor drivability differences on cold starts are possible
  • Dashes or an unrealistic (very low) temperature on the display

Possible causes

  1. Failed ambient air temperature sensor
  2. Signal wire shorted to ground in circuit B
  3. Damaged, corroded or water-filled connector
  4. Chafed harness near the bumper or radiator grille
  5. Problem with the 5 V reference or sensor ground
  6. Faulty control module (rare)

How to diagnose

  1. Scan all codes and freeze frame data, clear the code and see if it returns
  2. Compare the scan tool reading with actual air temperature and other temperature sensors on a cold engine
  3. Inspect the sensor, connector and harness for damage, moisture and corrosion
  4. Unplug the sensor: if the reading goes to the expected open-circuit value, the sensor or the signal wire is at fault
  5. Measure the sensor resistance and compare it with the spec for that temperature
  6. Check for 5 V reference and a good ground at the connector
  7. Test the signal wire for a short to ground and for opens back to the module
  8. If wiring and sensor are good, evaluate the control module

Common fixes

  • Replace the ambient air temperature sensor
  • Repair the wiring or replace the damaged harness section
  • Clean or replace the connector
  • Restore the sensor ground or reference supply
  • Repair or reflash the control module (rare)

Questions and answers

What does P00DB mean?

The control module sees a signal that is too low from the ambient air temperature sensor in circuit B. The cause is usually the sensor, a short to ground or a damaged connector.

Can I drive with P00DB?

Yes, usually. It rarely harms the engine, but the outside temperature display and climate control may be wrong, so don't put the repair off for long.

How do I fix P00DB?

Start by inspecting the sensor, connector and harness. Then test the sensor resistance and check the circuit for a short to ground. Replacing the sensor or repairing the wiring 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.