OBD Guide
ENFRDEESPT

P1A66

Starter/Generator Control Module Loop Overrun

P1A66 is an OBD-II diagnostic trouble code meaning: Starter/Generator Control Module Loop Overrun. Common causes: open or short circuit in control circuit, starter/generator module malfunction. Estimated repair cost: $56–278.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$56–278 (est.)

Symptoms

  • Difficulty starting the engine
  • Check Engine Light Flashing
  • Generator power reduction
  • Intermittent operation of the start-stop system

Causes

  • Open or short circuit in control circuit
  • Starter/Generator Module Malfunction
  • Problems with the module software
  • Wiring harness damage
  • Contact corrosion

How to Fix

  1. Check the integrity of the control circuit
  2. Scan the module for errors
  3. Check connections and contacts
  4. Replace starter/alternator module if necessary
  5. Update module software

Related codes

P1A67P1A68

FAQ

What does the P1A66 code mean?

P1A66 is an OBD-II diagnostic trouble code that indicates: Starter/Generator Control Module Loop Overrun

What causes a P1A66 error code?

The most common causes of P1A66 include: Open or short circuit in control circuit; Starter/Generator Module Malfunction; Problems with the module software; Wiring harness damage.

How do I fix a P1A66 diagnostic trouble code?

To fix P1A66: Check the integrity of the control circuit. Scan the module for errors. Check connections and contacts. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P1A66?

Limited driving only, diagnose soon

How much does it cost to fix P1A66?

The estimated repair cost for P1A66 is $56–278. Actual cost depends on your vehicle, location, and labor rates.

FRDEESPT

See also: Russian version · NationStat