Nissan Cedric P1629 Engine Trouble Code
What is Nissan Cedric P1629?
When Nissan Cedric 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 Nissan Cedric
The Nissan Cedric has a known weak point in the lambda sensor wiring loom where it passes through the floor pan grommet. Road salt and vibration cause the insulation to crack at this point, creating an intermittent open circuit that stores P1629 without a consistent symptom.
Code Information
| Code Type: | OBD-II Powertrain (P) Trouble Code |
| System: | Powertrain |
| Vehicle: | Nissan Cedric |
| Brand: | Nissan |
| Model: | Cedric |
| Code: | P1629 |
P1629 Nissan Cedric Symptoms
Check Engine Light
Illuminated Nissan Cedric dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration on the Nissan Cedric
Starting Problems
Difficulty starting the engine
Poor Fuel Economy
Increased fuel consumption on the Nissan Cedric
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 Nissan Cedric 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:
Gasoline engines use spark plugs to ignite fuel-air mixture. Proper timing ensures the explosion occurs when the piston is positioned correctly. Incorrect plug wire sequencing causes mistimed ignition, resulting in poor performance.
Technical Notes:
P1629 DTC specifically relates to camshaft timing. When cam timing is over-retarded, the check-engine light illuminates and this code sets. Verify VCT solenoid operation and check for contamination.
Nissan Cedric P1629 Repair Cost
MAF sensor replacement on the Nissan Cedric for a P1629 fault runs $220–$380 at a franchised dealer. OEM-equivalent aftermarket sensors are available for $80–$130 and are a reliable option for vehicles outside the factory warranty period.
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 Nissan Cedric
A catalytic converter is often condemned on the Nissan Cedric when P1629 appears and an efficiency code is present. Before replacement, verify that the upstream oxygen sensor is not slow-responding — a lazy O2 sensor mimics catalytic inefficiency perfectly.
DIY Repair Guide: P1629 on Nissan Cedric
For the Nissan Cedric, 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 Nissan Cedric
Spark plug replacement at the manufacturer's interval — typically 30,000–60,000 miles depending on plug type — is the single most cost-effective preventive maintenance item for avoiding P1629 on the Nissan Cedric.
Frequently Asked Questions — Nissan Cedric P1629
A: Yes. Any stored fault code — including P1629 — will cause an automatic failure in most OBD-II based emissions tests. The code must be resolved and the vehicle must complete a full OBD drive cycle with no new codes before the test.