Opel Kadett P1629 Engine Trouble Code
What is Opel Kadett P1629?
The Opel Kadett P1629 check-engine light can indicate issues ranging from minor (loose gas cap) to serious (catalytic converter failure). Professional diagnostic scanning at a dealer or shop will identify the exact cause and required repairs.
P1629 on the Opel Kadett
Owners of the Opel Kadett should be aware that P1629 can appear alongside oil consumption warnings. Low oil pressure caused by a worn PCV system lets crankcase vapour contaminate the mass air flow sensor, sending erroneous readings to the ECU.
Code Information
| Code Type: | OBD-II Powertrain (P) Trouble Code |
| System: | Powertrain |
| Vehicle: | Opel Kadett |
| Brand: | Opel |
| Model: | Kadett |
| Code: | P1629 |
P1629 Opel Kadett Symptoms
Check Engine Light
Illuminated Opel Kadett dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration on the Opel Kadett
Starting Problems
Difficulty starting the engine
Poor Fuel Economy
Increased fuel consumption on the Opel Kadett
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 Opel Kadett P1629
Diagnostic Steps:
Check if fuel pump primes when key is turned to ON. Measure fuel pressure and verify bright white-blue spark at all plugs. Also verify mechanical timing alignment.
Repair Solution:
Excessive air inflow may result from vacuum leaks, dirty sensors, or EGR valves not closing properly. Insufficient fuel can stem from dirty injectors, clogged filters, weak fuel pump, or leaking pressure regulator.
Technical Notes:
P1629 DTCs can be triggered by upstream issues. For example, a dirty MAF sensor may cause incorrect fuel-trim adjustments, leading oxygen sensors to report mixture problems. Address root causes first.
Opel Kadett P1629 Repair Cost
Torque converter clutch solenoid replacement on the Opel Kadett — relevant for owners who tow regularly — costs $280–$480. A full transmission fluid change ($120–$160) at the same service is recommended because contaminated fluid accelerates solenoid wear.
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 Opel Kadett
Some Opel Kadett 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 Opel Kadett
The coolant temperature sensor on the Opel Kadett is a straightforward DIY item (difficulty 2/5). Have a drain tray ready for the small amount of coolant that spills when the sensor is removed. Top up the cooling system afterwards and check for air pockets.
Preventing P1629 on the Opel Kadett
Using only genuine or OEM-specification fuel injectors in the Opel Kadett ensures precise spray pattern and flow rate. Inferior aftermarket injectors are a documented trigger for P1629 through off-target fuel delivery.
Frequently Asked Questions — Opel Kadett P1629
A: Temporarily clearing P1629 can help determine whether it is intermittent or persistent, but it does not fix the underlying fault. The code will return if the problem is still present. Do not clear codes just before an emissions test without a proper drive cycle.