Engine & fuel system
1 documented fault — symptoms, causes and workshop fixes.
Engine runs erratically
Symptoms
Trouble code stored in engine control module (ECM) fault memory: P1170.
Cause
Faulty heated oxygen sensor (HO2S).
Repair
- Renew heated oxygen sensor (HO2S).
Data: Motorwise Workshop. Bulletin 1.
Glossary
Technical terms used in this guide.
- ECM
- Engine control module — the electronic unit that manages the engine
- Control Module
- A control unit for one of the vehicle's systems (engine, gearbox, brakes, body, and so on)
- Fault Memory
- The list of stored trouble codes in a control module
- Trouble Code
- A standardised fault code stored by a control module, read with a diagnostic tool
Frequently asked questions
What are the common faults with the Mazda 626 2.0?
This guide contains one workshop bulletin for the Mazda 626 2.0. Of these, one concerns the engine and fuel system. Symptoms, causes, repair steps and part numbers are shown where supplied.
Does every Mazda 626 2.0 have these faults?
No. These are patterns documented across the model by workshops, not predictions for an individual vehicle. Where a fault applies only to certain vehicles or VIN ranges, that is listed with the fault.
Can I check for Mazda 626 2.0 faults myself?
Many of them. The documented symptoms can be seen, heard or felt during a test drive.