VOLVO
ABS-0030 - Left rear wheel sensor. Signal missing. Intermittent fault
System
Anti-lock Braking System (ABS)
Volvo models this fault code applies to
This fault code has different meanings depending on model, model year or engine. Select the meaning that applies to your car.
Applies to the following models:
5 modelsC70 Cabriolet (1998–2005), C70 Coupé (1998–2002), S70 (1997–2000), V70 (1997–2000), V70 XC (1998–2000)
What does this fault code mean?
The ABS control module has at times lost the signal from the wheel speed sensor on the left rear wheel. The fault is intermittent, meaning it is sporadic and may not be present right now. It is often caused by a temporary poor contact or a cable break that only shows when the car is moving. The equivalent code for the right rear wheel is ABS-0040.
Possible causes
- Poor contact in the connections at the sensor or the module
- Open circuit or short to ground or supply voltage in the sensor supply
- Signal wires briefly shorted to each other
- Open circuit in the signal wire that only appears when the cable moves
- Faulty wheel speed sensor or, less commonly, a faulty ABS control module
What you can do
- 1Read the code, clear it and road test to see whether the fault returns
- 2Check the connector at the left rear wheel sensor for looseness, moisture and corrosion
- 3Check the connector at the module and the wiring between the module and the sensor for intermittent open circuits
- 4Follow the cable from the sensor and look for chafing and pinched sections, especially at moving parts
- 5If the fault remains or returns often, have a workshop with diagnostic equipment check the wiring
- 6ABS is safety-critical – avoid hard braking until the fault is fixed and do not let anyone unqualified work on the brake system
Symptoms you may notice4
- ABS and traction control warning lamps lit
- Brake system warning lamp lit
- ABS and traction control do not work
- The ABS warning lamp may only go out some way into the next drive
What the fault can affect2
- ABS and traction control are blocked
- Brake force distribution is disabled if two or more sensors stop working
General guidance for car owners. Diagnosis on the car can point to a different cause.