Lost Communication With Steering Effort Control Module

Possible causes

• CommonLow battery voltage or a discharged battery, dropping modules off the bus
• CommonBlown fuse or corroded earth on the supply to the steering effort control module
• CommonDamaged, chafed or corroded bus wiring
• CommonCorroded or water-ingressed connector at the module
• PossibleFailed module
• PossibleAnother module faulting and dragging the whole bus down
• PossibleModule not coded or configured after a previous repair or replacement

What you might notice

• Steering suddenly much heavier than normal
• Power steering warning light on
• Steering assistance coming and going
• Other warning lights on at the same time
• Sometimes no symptom, if the fault was momentary

What to check, in order

1. Treat heavy steering as a reason to stop rather than a reason to continue and monitor. Assistance that has already dropped out once can drop out again at any speed.
2. Check battery voltage and state of charge before anything else. A weak or failing battery drops modules off the bus and sets lost-communication codes with no wiring fault at all - this is the single most common false lead in this whole family.
3. Check whether this code is current or historic. Lost-communication codes are routinely set by a flat battery, a jump start or a battery disconnection, and a historic code straight after one of those events usually records the event rather than a fault.
4. Check the fuses and earth points for the steering effort control module.
5. Note how many U-codes are stored. Several at once points at battery, earth or bus wiring, not at several modules failing simultaneously.
6. Inspect the module connector for corrosion and water ingress.
7. Do not condemn the module until power, earth, bus wiring and battery condition have all been eliminated. Steering modules are expensive and are usually innocent.