Engine & fuel system
2 documented faults — symptoms, causes and workshop fixes.
Engine malfunction indicator lamp (MIL) illuminated. Trouble code stored: P2135
Overview
- Affects
- All models, →19/08/10.
- Fault codes
P2135- Remedy
- Fit modified part
- Parts
- 2 parts
Cause
Open circuit/high resistance in wiring harness between engine control module (ECM) and throttle position (TP) sensor.
Throttle position (TP) sensor faulty.
Repair
- Check for open circuit/high resistance in wiring harness between engine control module (ECM) and throttle position (TP) sensor. Repair as necessary.
- If no fault(s) found: Fit modified throttle body.
Parts2 parts
| Part | Part number | Qty |
|---|---|---|
| Throttle body | CA01-13640-B | 1 |
| Throttle body gasket | CY01-13655 | 1 |
Data: Motorwise Workshop. Bulletin 1.
Oil leak from rear differential
Unsatisfactory design of rear differential breather valve causing pressure build up in rear differential. Fix: fit a modified part.
Overview
- Affects
- All models with four wheel drive, →07/11.
- Remedy
- Fit modified part
Repair steps
- Fit new driveshaft oil seals.
- Fit modified rear differential breather valve.
- Fit protective boot to rear differential breather valve. Ensure protective boot ventilation hole faces rear of vehicle.
Parts
| Part | Part number | Qty |
|---|---|---|
| Rear differential breather valve | B39M 26 060 | 1 |
| Protective boot | B39M 27 763 | 1 |
| Driveshaft oil seal | M0A7 27 238A | 2 |
Data: Motorwise Workshop. Bulletin 6.
Electrical & ignition
1 documented fault — symptoms, causes and workshop fixes.
Failure of left or right headlamp
Overview
- Affects
- All models with gas discharge headlamps.
- Remedy
- Fit new part
Cause
Headlamp igniter unit not fitted correctly causing poor connection.
Repair
- Ensure headlamp igniter unit is disconnected from power supply.
- Fit new headlamp bulb and headlamp igniter unit. Turn headlamp igniter unit fully clockwise until it locks into position.
Data: Motorwise Workshop. Bulletin 4.
Brakes
3 documented faults — symptoms, causes and workshop fixes.
ABS warning lamp illuminates when turning whilst driving up hill or down hill
Overview
- Affects
- All models.
- Remedy
- Fit modified part
Cause
Faulty ABS/ASC/DSC control module.
Repair
- Carry out electrical, mechanical and component tests (as applicable) to eliminate any other possible cause(s).
- If no fault(s) found: Fit modified ABS/ASC/DSC control module.
Data: Motorwise Workshop. Bulletin 2.
Brake fluid level warning lamp illuminated even though brake fluid level correct
Symptoms
Trouble code stored in ABS control module fault memory: C1327.
Cause
Brake fluid level switch faulty.
Repair
- Fit new brake fluid reservoir.
Data: Motorwise Workshop. Bulletin 3.
Groaning noise from rear brakes when brakes applied
Vibration between brake pads and discs. Fix: fit a modified part.
Overview
- Affects
- All models.
- Remedy
- Fit modified part
Repair steps
- Remove rear brake pads.
- Clean mating surfaces of brake caliper and carrier.
- Apply grease to contact surfaces of rear brake pad back plates.
- Fit modified rear brake pads. Ensure brake pad anti-squeal shims are fitted.
Data: Motorwise Workshop. Bulletin 5.
Glossary
Technical terms used in this guide.
- ECM
- Engine control module — the electronic unit that manages the engine
- ABS
- Anti-lock braking system — stops the wheels locking under hard braking
- Caliper
- The part that squeezes the brake pads onto the disc
- Control Module
- A control unit for one of the vehicle's systems (engine, gearbox, brakes, body, and so on)
- Driveshaft
- The shaft that takes drive from the differential out to a wheel
- 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
- Wiring Harness
- The bundled cables that carry power and signals around the vehicle
Frequently asked questions
What are the common faults with the Mazda CX-9 3.7?
This guide contains six workshop bulletins for the Mazda CX-9 3.7. Of these, three concern the brakes and two the engine and fuel system. Symptoms, causes, repair steps and part numbers are shown where supplied.
Does every Mazda CX-9 3.7 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 CX-9 3.7 faults myself?
Many of them. The documented symptoms can be seen, heard or felt during a test drive.