Toyota Corona P1629 Engine Trouble Code
What is Toyota Corona P1629?
When Toyota Corona P1629 code appears, first check your gas cap. Pull over safely, ensure it is tight, and inspect for cracks. A loose or damaged gas cap affects fuel-system pressure and emissions. A replacement cap costs about $3–$10. This simple fix can resolve the code and improve fuel economy.
P1629 on the Toyota Corona
Many Toyota Corona drivers first encounter P1629 as a result of worn ignition coil packs. The design of the Toyota engine bay can trap heat near these components, accelerating wear beyond the typical service interval.
Code Information
| Code Type: | OBD-II Powertrain (P) Trouble Code |
| System: | Powertrain |
| Vehicle: | Toyota Corona |
| Brand: | Toyota |
| Model: | Corona |
| Code: | P1629 |
P1629 Toyota Corona Symptoms
Check Engine Light
Illuminated Toyota Corona dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration on the Toyota Corona
Starting Problems
Difficulty starting the engine
Poor Fuel Economy
Increased fuel consumption on the Toyota Corona
Increased Emissions
Failed emissions test due to P1629
P1629 Code Structure
Understanding what each digit means in the P1629 powertrain trouble code:
| P | 1 | 6 | 2 | 9 |
|---|---|---|---|---|
| Powertrain Code | Fuel And Air Metering | Fuel Temperature Sensor B Circuit Range/Performance | Turbocharger Boost Sensor A Circuit Low | Reverse Input Circuit |
How to Fix Toyota Corona P1629
Diagnostic Steps:
Oxygen sensors measure exhaust gas oxygen content to optimise air-fuel ratio. This optimisation improves fuel economy and reduces emissions. Sensors degrade over time and require periodic replacement.
Repair Solution:
Crankshaft position sensor signals the computer for precise ignition and fuel injection timing. Faulty sensors cause rough running and reduced efficiency. Modern vehicles enter limp mode and illuminate the check-engine light.
Technical Notes:
Parts or components should not be replaced based solely on P1629 DTC. Consult your vehicle service manual for proper diagnostic procedures, possible causes, and required testing before replacement.
Toyota Corona P1629 Repair Cost
Throttle body cleaning and idle relearn on the Toyota Corona for a P1629 diagnosis costs $60–$100 at an independent shop. If a full throttle body replacement is needed (rare), expect $250–$450 including programming the unit to the ECU.
P1629 Description
P1629 engine trouble code is related to Reverse Input Circuit.
Main Cause
The primary reason for P1629 OBD-II Engine Trouble Code is: Fuel Temperature Sensor B Circuit Range/Performance.
Common P1629 Misdiagnosis on the Toyota Corona
Some Toyota Corona models have a known software bug where the PCM flags P1629 after battery disconnection and reconnect. Always perform an ECU adaptation reset and drive cycle before ordering any parts following battery work.
DIY Repair Guide: P1629 on Toyota Corona
For the Toyota Corona, an EGR valve inspection is a useful DIY step before spending money on diagnosis. Remove the valve (2–4 bolts depending on generation), inspect for carbon build-up, and use carburettor cleaner and a soft brass brush to clean the valve face and seat.
Preventing P1629 on the Toyota Corona
To keep the Toyota Corona free of recurring P1629 faults, change the engine oil every 5,000–7,500 miles using a grade specified by Toyota. Oil viscosity directly affects VVT actuator response, and using the wrong grade is one of the most avoidable causes of this code.
Frequently Asked Questions — Toyota Corona P1629
A: Not always. Across model years, Toyota revised sensor specifications, wiring paths, and ECU calibrations. Always confirm the repair procedure matches your specific vehicle's production year and engine code, as parts and labour times can vary significantly.