Engine & fuel system
2 documented faults — symptoms, causes and workshop fixes.
Fuel gauge fluctuates
Faulty fuel gauge tank sensor/ventilation assembly.
Overview
- Affects
- All models, →11/09.
Repair steps
- Remove fuel gauge tank sensor/ventilation assembly.
- Transfer fuel gauge tank sensor to new ventilation assembly.
- Fit fuel gauge tank sensor/ventilation assembly.
Data: Motorwise Workshop. Bulletin 1.
Reduced engine performance
Carbon deposit build up in exhaust gas recirculation (EGR) system. Fix: fit a modified part.
Overview
- Affects
- All models with 1KR-FE engine code, →06/10.
- Remedy
- Fit modified part
Symptoms
Loss of engine power on acceleration.
Repair steps
- Carry out electrical, mechanical and component tests (as applicable) to eliminate any other possible cause(s).
- If no fault(s) found: Clean or replace EGR system components as necessary.
- If EGR pipe located upstream of catalytic converter: Fit modified catalytic converter (EGR pipe located downstream of catalytic converter).
Data: Motorwise Workshop. Bulletin 2.
Brakes
1 documented fault — symptoms, causes and workshop fixes.
Poor performance of parking brake
Cause
Unsatisfactory design of handbrake cables.
Repair
- Fit modified handbrake cables.
Parts2 parts
| Part | Part number | Qty |
|---|---|---|
| Handbrake cable, left | 46430-74021 | 1 |
| Handbrake cable, right | 46420-74021 | 1 |
Data: Motorwise Workshop. Bulletin 5.
Suspension & drivetrain
1 documented fault — symptoms, causes and workshop fixes.
Knocking noise from front suspension over uneven surfaces
Overview
- Affects
- All models.
- Remedy
- Fit modified part
- Parts
- 1 part
Cause
Unsatisfactory design of front lower suspension arm front retaining bolt.
Repair
- Fit modified front lower suspension arm front retaining bolt.
- Tighten retaining bolts to the correct torque of 145±18 Nm.
Parts1 part
| Part | Part number | Qty |
|---|---|---|
| Bolt | 90119-14150 | 2 |
Data: Motorwise Workshop. Bulletin 3.
Body & trim
1 documented fault — symptoms, causes and workshop fixes.
Door handles sticking in open position in very cold conditions
Cause
Door handle frozen due to poor water drainage.
Repair
- Fit modified door handles.
Data: Motorwise Workshop. Bulletin 6.
Other
1 documented fault — symptoms, causes and workshop fixes.
Poor performance or failure of AC system
Cause
AC compressor faulty.
Repair
- Fit modified AC compressor.
Data: Motorwise Workshop. Bulletin 4.
Glossary
Technical terms used in this guide.
- Nm
- Newton-metres — the standard unit for how tightly a bolt is done up
- EGR
- Exhaust gas recirculation — feeds some exhaust gas back into the intake to cut emissions
- AC
- Air conditioning — the system that cools the cabin
- Recirculation
- Air-conditioning mode that recirculates cabin air instead of drawing in outside air
Frequently asked questions
What are the common faults with the Toyota iQ 1.0 VVT-i?
This guide contains six workshop bulletins for the Toyota iQ 1.0 VVT-i. Of these, two concern the engine and fuel system and one the brakes. Symptoms, causes, repair steps and part numbers are shown where supplied.
Does every Toyota iQ 1.0 VVT-i 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 Toyota iQ 1.0 VVT-i faults myself?
Many of them. The documented symptoms can be seen, heard or felt during a test drive.