VOLVO
ABS-0020 - Right front 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 some point lost the signal from the wheel speed sensor on the right front wheel. The fault is intermittent, meaning the signal has dropped out from time to time and may be normal right now. The equivalent code for the left front wheel is ABS-0010.
Possible causes
- Contact resistance in the connections, for example a loose connector at the sensor or module
- Open circuit or short to ground or supply voltage in the sensor supply
- Signal wires briefly shorted to each other
- Signal wire briefly shorted to ground or supply voltage, or briefly open
- 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 it returns
- 2Check the connectors at the right front wheel sensor and at the ABS control module for loose contacts and oxidation
- 3Follow the sensor wiring from the wheel arch and look for chafing, pinching and loose clips
- 4If the fault returns, have a workshop with diagnostic equipment check the sensor signal and the wiring
- 5The cable may have moved with the suspension, so check that it is routed correctly and secured
- 6ABS is safety-critical – do not work on the ABS control module or the brake system yourself, have a workshop do it
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 wheel sensors malfunction
General guidance for car owners. Diagnosis on the car can point to a different cause.