Mazda2002–2005

6 2.3: Common faults & known problems

Common faults & known problems

11 known faults documented in workshop bulletins. Of these, five concern the engine and fuel system and two the electrical and ignition. Symptoms, causes, repair steps and part numbers are shown where supplied.

Technical specifications

Engine & fuel system

5 documented faults — symptoms, causes and workshop fixes.

Engine malfunction indicator lamp (MIL) illuminated

Affects All models with L3/L3 turbo/LF engine codes: 3: →12/07. 6: →06/07. MX-5: →12/07. 5: 2006-07. CX-7: →12/07.P0440Fit new part

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

Parts listed in the bulletin
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

Parts listed in the bulletin
Part	Part number	Qty
Cleaning spray	000-77-A86	1
Throttle body gasket	L321-13-655C	1

Data: Motorwise Workshop. Bulletin 4.

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

Parts listed in the bulletin
Part	Part number	Qty
Cleaning spray	000-77-A86	1
Throttle body gasket	L3G2-13-655	1

Data: Motorwise Workshop. Bulletin 5.

Unable to lift engine from engine bay

Affects All models.

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

Affects All models with petrol engines.

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.

Brakes

2 documented faults — symptoms, causes and workshop fixes.

Front brake judder

Overview

Affects: All models, →10/03.
Remedy: Fit modified part
Parts: 2 parts

Cause

Front brake disc distortion.

Repair

Fit new front brake discs.
Fit modified front brake pads.

Parts2 parts

Parts listed in the bulletin
Part	Part number	Qty
Front brake disc	GK2Y-33-25XE	2
Front brake pads	G2Y2-33-23ZA	1

Data: Motorwise Workshop. Bulletin 2.

Noise from front brakes when brakes applied at slow speed

Affects All models, →10/03.Fit modified part

Cause

Vibration between brake pads and discs.

Repair

Fit modified front brake pads.

Parts1 part

Parts listed in the bulletin
Part	Part number	Qty
Front brake pads	G2Y2-33-23ZA	1

Data: Motorwise Workshop. Bulletin 3.

Clutch & gearbox

1 documented fault — symptoms, causes and workshop fixes.

Whining/grinding noise from front of engine

Affects All models.

Symptoms

Excessive noise from auxiliary drive belt.

Cause

Failure of alternator pulley clutch.

Repair

Replace alternator.

Data: Motorwise Workshop. Bulletin 11.

Other

1 documented fault — 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 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
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
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?

This guide contains 11 workshop bulletins for the Mazda 6 2.3. Of these, five 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 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 faults myself?

Many of them. The documented symptoms can be seen, heard or felt during a test drive.