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U0407 — Invalid Data Received From Glow Plug Control Module 1

Generic OBD-II · all makesNetwork / communication

U0407 indicates that the engine control module (ECM) has received invalid, missing, or corrupted data from the glow plug control module (GPCM) over the vehicle's communication network. This code is typically set on diesel engines and points to a communication fault rather than a direct glow plug failure.

Symptoms

What causes it — most likely first

1. Faulty glow plug control module

The GPCM itself is the most common failure. Internal electronics can fail due to heat, vibration, or age, causing it to stop communicating properly with the ECM.

2. Damaged or corroded wiring/connectors

Chafed, broken, or corroded wires in the harness between the GPCM and ECM, or poor pin contact at connectors, can disrupt data transmission.

3. Low battery voltage or charging system issue

Insufficient voltage (below ~10.5V during cranking) can cause the GPCM to malfunction or fail to communicate. A weak battery or failing alternator is a common underlying cause.

4. Faulty glow plugs

While less common as a direct cause of U0407, shorted or open glow plugs can overload the GPCM or cause it to report invalid data, triggering the code.

5. CAN bus communication fault

A problem on the Controller Area Network (CAN) bus, such as a short, open, or excessive noise, can prevent valid data from reaching the ECM. This may affect multiple modules.

6. Engine control module (ECM) failure

Rare, but a failing ECM can misinterpret or fail to receive data from the GPCM. This should only be considered after all other causes are ruled out.

How it's diagnosed

  1. Scan for all stored codes and freeze frame data; note any other communication or glow plug related codes.
  2. Check battery voltage and charging system; ensure battery is fully charged and alternator output is within spec.
  3. Visually inspect the GPCM connector and wiring harness for corrosion, damage, or loose pins. Repair as needed.
  4. Test power and ground circuits at the GPCM using a multimeter; verify at least battery voltage with ignition on.
  5. Perform a communication test (e.g., using a scan tool to see if GPCM responds or if CAN bus signals are present).
  6. If wiring and power are good, suspect the GPCM itself; test or replace it. Only consider ECM replacement if all other components and wiring are verified and the code persists.

Code facts & related codes

SystemNetwork / communication
StandardizationSAE generic — identical on every make
Related codesU0400 — Invalid Data ReceivedU0401 — Invalid Data Received From EcmpcmU0402 — Invalid Data Received From TcmU0403 — Invalid Data Received From Transfer CaU0404 — Invalid Data Received From Gear Shift U0405 — Invalid Data Received From Cruise Cont

Frequently asked

Can I drive my vehicle with code U0407?

You can usually drive, but you may experience hard starting, reduced power, or limp mode. In cold weather, the vehicle may not start at all. It's best to diagnose and repair promptly to avoid being stranded.

Is it likely the ECM (engine computer) needs to be replaced?

No. For U0407, the ECM is rarely the cause. The glow plug control module, its wiring, or the battery/charging system are far more common. Replacing the ECM without proper diagnosis is usually a waste of money.

Do I need to replace all glow plugs when I get this code?

Not necessarily. U0407 is a communication code, not a glow plug circuit code. However, if a scan tool shows glow plug faults alongside U0407, those plugs should be tested and replaced individually as needed.

Will clearing the code fix the problem?

Clearing the code may turn off the check engine light temporarily, but if the underlying fault (e.g., a failed GPCM) is not repaired, the code will return. Use clearing only after repairs are completed.