Engine & fuel system
6 documented faults — symptoms, causes and workshop fixes.
Engine malfunction indicator lamp (MIL) illuminated
Symptoms
Engine runs in limp home mode. Trouble code stored: P0440.
Cause
Evaporative emission (EVAP) canister purge valve faulty.
Repair
- Fit new evaporative emission (EVAP) canister purge valve.
Parts7 parts
| Part | Part number | Qty |
|---|---|---|
| EVAP valve | LF66-20-360K | 3 (→2005) |
| EVAP valve | L32D-20-360D | 3 (2006→) |
| EVAP valve | L391-18-740C | 6 (→2005) |
| EVAP valve | L3P9-18-740B | 6 (2006→) |
| EVAP valve | LFG1-18-741B | MX-5 |
| EVAP valve | L3P5-20-360B | 5 |
| EVAP valve | L33L-18-740B | CX-7 |
Data: Motorwise Workshop. Bulletin 1.
Erratic idle. No trouble codes stored in fault memory
Throttle body contaminated with carbon deposits. Fix: clean and lubricate.
Overview
- Affects
- All models.
- Remedy
- Clean & lubricate
Symptoms
Engine stalls at idle. No trouble codes stored in fault memory. Engine stalls/cuts out when vehicle comes to a standstill. No trouble codes stored in fault memory.
Repair steps
- Remove throttle body.
- Clean carbon deposits from throttle body.
- Refit throttle body. Renew throttle body gasket.
- Initialise throttle control unit as follows: Switch ignition ON. Wait 1 minute. Switch ignition OFF. Wait 1 minute. Start engine. Allow engine to idle. Ensure all electrical equipment switched OFF. Allow engine to reach normal operating temperature. Check that idle speed remains within specification.
Parts
| Part | Part number | Qty |
|---|---|---|
| Cleaning spray | 000-77-A86 | 1 |
| Throttle body gasket | L3K9-13-655 | 1 |
Data: Motorwise Workshop. Bulletin 2.
Excessive noise from camshaft position (CMP) actuator, especially when starting from cold
Camshaft position (CMP) actuator locking pin not fully engaging. Fix: fit a modified part.
Overview
- Affects
- All models, →04/07.
- Remedy
- Fit modified part
Repair steps
- Fit modified camshaft position (CMP) actuator.
- Change engine oil.
- Start engine. Allow engine to idle for a minimum of 5 minutes.
- Check high-pressure fuel pump for leaks.
- Switch ignition OFF.
- Allow engine to cool.
- Change engine oil and filter.
Parts
| Part | Part number | Qty |
|---|---|---|
| Camshaft position (CMP) actuator | L3K9-12-4X0B | 1 |
| Washer | L3K9-12-4X0B | 2 |
| Engine oil | 0000-77-5W30-QT | 11,4 litres |
| Engine oil filter | L321-14-302-9U | 1 |
| Bolt | LF01-11-406 | 1 |
| Engine oil sump drain plug | 9XG0-99-667L | 1 |
Data: Motorwise Workshop. Bulletin 3.
Excessive white smoke from exhaust during acceleration
Cause
Turbocharger (TC) oil seals faulty.
Repair
- Fit modified turbocharger (TC).
Data: Motorwise Workshop. Bulletin 4.
Unable to lift engine from engine bay
Cause
Engine bay too narrow for engine to be lifted out.
Repair
- Remove engine and transmission from underneath the vehicle.
Data: Motorwise Workshop. Bulletin 7.
Poor starting from cold
Cause
Engine coolant temperature (ECT) sensor faulty.
Repair
- Replace engine coolant temperature (ECT) sensor.
Data: Motorwise Workshop. Bulletin 8.
Electrical & ignition
2 documented faults — symptoms, causes and workshop fixes.
Intermittent failure of indicators/hazard warning lamps. Blown fuse
Overview
- Affects
- All models.
Cause
Exterior lighting wiring harness chafes against AC high-pressure pipe, located under LH headlamp, causing short circuit.
Repair
- Repair wiring harness as necessary.
- Replace fuse.
Data: Motorwise Workshop. Bulletin 9.
Indicators flash erratically
Overview
- Affects
- All models.
- Remedy
- Fit new part
Symptoms
Intermittent failure of indicators/hazard warning lamps.
Cause
Multifunction control module faulty.
Repair
- Carry out electrical, mechanical and component tests (as applicable) to eliminate any other possible cause(s).
- If no fault(s) found: Fit new multifunction control module.
Data: Motorwise Workshop. Bulletin 10.
Clutch & gearbox
1 documented fault — symptoms, causes and workshop fixes.
Whining/grinding noise from front of engine
Symptoms
Excessive noise from auxiliary drive belt.
Cause
Failure of alternator pulley clutch.
Repair
- Replace alternator.
Data: Motorwise Workshop. Bulletin 11.
Other
2 documented faults — symptoms, causes and workshop fixes.
Heated oxygen sensor (HO2S) seized in catalytic converter
Overview
- Affects
- All models with L3/L3 turbo engine codes.
- Remedy
- Clean & lubricate
Cause
Chemical reaction between materials causing components to bond together.
Repair
- Lubricate heated oxygen sensor (HO2S) threads with penetrating oil when removing.
- Inspect heated oxygen sensor (HO2S) threads. Replace component(s) as necessary.
Data: Motorwise Workshop. Bulletin 5.
Knocking noise from rear differential when down-shifting gears
Overview
- Affects
- All models with four wheel drive.
Cause
Incorrect tyre pressures and/or mismatched tyres.
Repair
- Check all tyres are to manufacturer's specification.
- Check tyre condition and tyre pressures.
Data: Motorwise Workshop. Bulletin 6.
Glossary
Technical terms used in this guide.
- Trouble Codes
- Standardised fault codes stored by the engine control module, read with a diagnostic tool
- AC
- Air conditioning — the system that cools the cabin
- CMP
- Camshaft position — a sensor that tells the engine control module where the camshaft is
- ECT
- Engine coolant temperature — the sensor that tells the engine control module how hot the engine is
- LH
- Left-hand — the left side of the vehicle as you sit in it
- TC
- Turbocharger — the exhaust-driven compressor that boosts engine power
- Actuator
- A motor or solenoid that moves a mechanical part on command
- Engine Coolant Temperature
- How hot the engine is, read by a sensor the engine control module uses for fuelling and cooling fans
- Fault Memory
- The list of stored trouble codes in a control module
- Limp Home
- A protective mode that limits power so the vehicle can be driven to a workshop
- Multifunction Control Module
- The control module that runs shared electrical functions (lights, wipers, locking, and so on)
- Trouble Code
- A standardised fault code stored by a control module, read with a diagnostic tool
- Wiring Harness
- The bundled cables that carry power and signals around the vehicle
- Alternator
- The unit that charges the battery while the engine is running
- Auxiliary Drive Belt
- The belt that drives the alternator, water pump, steering pump or air-conditioning compressor
- Initialise
- A workshop procedure that teaches a new module or system its starting values
Frequently asked questions
What are the common faults with the Mazda 6 2.3 MPS?
This guide contains 11 workshop bulletins for the Mazda 6 2.3 MPS. Of these, six concern the engine and fuel system and two the electrical and ignition. Symptoms, causes, repair steps and part numbers are shown where supplied.
Does every Mazda 6 2.3 MPS 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 6 2.3 MPS faults myself?
Many of them. The documented symptoms can be seen, heard or felt during a test drive.