Fault code lookup

NetworkU0078

Serious

Severity: Serious - have it checked soon

Control Module Communication Bus F Off

16 brands affected · Generic SAE J2012 description.

Key terms: Control module: a small computer that runs one part of the car · SAE J2012: the standard generic code list

1What it means in plain English

Control modules in the car cannot communicate with each other over the vehicle network.

2Common causes

  1. Wiring or connector fault on the communication bus
  2. Faulty control module
  3. Low battery voltage or poor ground
  4. Water ingress in a connector or module
  5. Aftermarket device interfering with the bus

3Can I drive?

Serious · drive with care

The car may run normally or may not run at all. If the module that has lost communication controls steering, brakes, park brake, charging or engine cooling, drive only if those systems feel normal; stop safely if the steering becomes heavy, a brake warning appears, or the engine temperature climbs. If the car will not start or runs badly, have it towed.

This page gives general information. It is not professional advice. For a definite diagnosis and a repair quote, ask a qualified mechanic to inspect the car.

4Brand data 16

BrandCodeDescriptionSystem
Ashok Leyland CVU0078Control Module Communication Bus F Off SAENetwork
DaewooU0078Control Module Communication Bus F Off SAENetwork
EOBDU0078Juhtmoduli sidebuss 'F' väljas BrandNetwork
GeelyU0078CAN message TCU check and fault BrandNetwork
GMU0078Control Module Communication Bus F Off SAENetwork
HoldenU0078Control Module Communication Bus F Off SAENetwork
Land RoverU0078Control Module Communication Bus 'F' Off BrandNetwork
MitsubishiU0078Control Module Communication Bus F Off SAENetwork
OpelU0078Control Module Communication Bus F Off SAENetwork
PeugeotU0078Control Module Communication Bus F Off SAENetwork
SaabU0078Control Module Communication Bus F Off SAENetwork
Maxus (SAIC)U0078Bus Off on EPT CAN BrandNetwork
MG (SAIC)U0078Bus Off on EPT CAN BrandNetwork
SubaruU0078Control Module Communication Bus F Off SAENetwork
SuzukiU0078Control Module Communication Bus F Off SAENetwork
ToyotaU0078Control module communication bus 'F' off BrandNetwork

Legend: SAE is the generic J2012 description; Brand is text taken from that manufacturer’s data. Manufacturer rows keep the wording and language of the source data, and non-English text is tagged so screen readers pronounce it correctly.

5Related codes

Browse Uxxx codes or U007xx codes.

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