OBD Guide
ENFRDEESPT

U1503

Implausible Message Data Length Received From FCM

U1503 is an OBD-II diagnostic trouble code meaning: Implausible Message Data Length Received From FCM. Common causes: damage to wiring between modules, fcm module malfunction. Estimated repair cost: $17–89.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$17–89 (est.)

Symptoms

  • Check Engine light comes on
  • Malfunctions of electronic body systems
  • Automatic headlight control failure
  • Problems with central locking

Causes

  • Damage to wiring between modules
  • FCM module malfunction
  • Problems with the communication bus (CAN)
  • Software error in FCM module

How to Fix

  1. Check the integrity of the wiring between the modules
  2. Check the condition of connectors and contacts
  3. Scan the FCM module for errors
  4. Update FCM software
  5. Repair only from an authorized dealer

Related codes

U1500U1501U1502

FAQ

What does the U1503 code mean?

U1503 is an OBD-II diagnostic trouble code that indicates: Implausible Message Data Length Received From FCM

What causes a U1503 error code?

The most common causes of U1503 include: Damage to wiring between modules; FCM module malfunction; Problems with the communication bus (CAN); Software error in FCM module.

How do I fix a U1503 diagnostic trouble code?

To fix U1503: Check the integrity of the wiring between the modules. Check the condition of connectors and contacts. Scan the FCM module for errors. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U1503?

Yes, but get it checked soon

How much does it cost to fix U1503?

The estimated repair cost for U1503 is $17–89. Actual cost depends on your vehicle, location, and labor rates.

FRDEESPT

See also: Russian version · NationStat