OBD Guide

P1503

Load Signal From Alternator DF Terminal Implausible Signal

P1503 is an OBD-II diagnostic trouble code meaning: Load Signal From Alternator DF Terminal Implausible Signal. Common causes: generator malfunction, open or short circuit in terminal df circuit. Estimated repair cost: $56–167.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$56–167 (est.)

Symptoms

  • Check Engine Light Is On
  • Unstable engine operation at idle
  • Battery charging problems
  • Reduced power of electrical equipment
  • Periodic malfunctions in the operation of car electronics

Causes

  • Generator malfunction
  • Open or short circuit in terminal DF circuit
  • Poor contact in connectors or corrosion
  • Engine control unit (ECU) malfunction
  • Relay or fuse problems

How to Fix

  1. Check the condition of the generator and its terminals
  2. Inspect the DF terminal circuit for damage.
  3. Check contacts and connectors for corrosion
  4. Test the generator on the stand
  5. If necessary, replace the generator or repair the wiring

Related codes

Error P1503 by Vehicle Brand

FAQ

What does the P1503 code mean?

P1503 is an OBD-II diagnostic trouble code that indicates: Load Signal From Alternator DF Terminal Implausible Signal

What causes a P1503 error code?

The most common causes of P1503 include: Generator malfunction; Open or short circuit in terminal DF circuit; Poor contact in connectors or corrosion; Engine control unit (ECU) malfunction.

How do I fix a P1503 diagnostic trouble code?

To fix P1503: Check the condition of the generator and its terminals. Inspect the DF terminal circuit for damage.. Check contacts and connectors for corrosion. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P1503?

Limited driving only, diagnose soon

How much does it cost to fix P1503?

The estimated repair cost for P1503 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat