DTC 425 - Rear Ho2S
WARNING: This page is about a different car, the 1996 Volvo 850. However, it is still accessible from the selected car via links, so may be relevant.
- Perform a compression check on all cylinders. See appropriate ADJUSTMENTS article. Repair as necessary. If compression is okay, go to next step.
- Check for air leakage in intake system. Repair as necessary. If there is no air leakage in intake system, check for air leakage in exhaust system. Repair as necessary. If there is no air leakage in exhaust system, check fuel and residual pressure. Repair as necessary. If fuel and residual pressure are okay, retest using new HO2S.