OBD Guide

P1A9B

Starter/Generator Inverter Phase U Temperature Sensor Performance

P1A9B is an OBD-II diagnostic trouble code meaning: Starter/Generator Inverter Phase U Temperature Sensor Performance. Common causes: phase u temperature sensor fault, open or short circuit in the sensor circuit. Estimated repair cost: $17–56.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$17–56 (est.)

Symptoms

  • Check Engine light comes on
  • Problems starting the engine
  • Reduced efficiency of the regenerative braking system
  • Incorrect operation of the starter/generator
  • Inverter overheating

Causes

  • Phase U temperature sensor fault
  • Open or short circuit in the sensor circuit
  • Poor contact in the sensor connector
  • Wiring harness damage
  • Starter/Generator Inverter Malfunction

How to Fix

  1. Check phase U temperature sensor
  2. Check the integrity of the sensor circuit
  3. Inspect connectors and contacts for corrosion or damage
  4. Check the operation of the starter/generator inverter
  5. Replace temperature sensor if necessary

Related codes

FAQ

What does the P1A9B code mean?

P1A9B is an OBD-II diagnostic trouble code that indicates: Starter/Generator Inverter Phase U Temperature Sensor Performance

What causes a P1A9B error code?

The most common causes of P1A9B include: Phase U temperature sensor fault; Open or short circuit in the sensor circuit; Poor contact in the sensor connector; Wiring harness damage.

How do I fix a P1A9B diagnostic trouble code?

To fix P1A9B: Check phase U temperature sensor. Check the integrity of the sensor circuit. Inspect connectors and contacts for corrosion or damage. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P1A9B?

Yes, but get it checked soon

How much does it cost to fix P1A9B?

The estimated repair cost for P1A9B is $17–56. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat