Bmw 1500 P1629 Engine Trouble Code
What is Bmw 1500 P1629?
When Bmw 1500 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 Bmw 1500
Many Bmw 1500 drivers first encounter P1629 as a result of worn ignition coil packs. The design of the Bmw 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: | Bmw 1500 |
| Brand: | Bmw |
| Model: | 1500 |
| Code: | P1629 |
P1629 Bmw 1500 Symptoms
Check Engine Light
Illuminated Bmw 1500 dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration on the Bmw 1500
Starting Problems
Difficulty starting the engine
Poor Fuel Economy
Increased fuel consumption on the Bmw 1500
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 Bmw 1500 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:
A/C pressure sensor monitors refrigerant pressure changes. DTC sets when pressure change falls outside calibration. Verify A/C system function, refrigerant charge, and electrical connections.
Technical Notes:
For P1629, verify VCT solenoid operation. Look for stuck or sticking valves caused by contamination. Consult vehicle-specific repair manual for proper component testing procedures.
Bmw 1500 P1629 Repair Cost
MAF sensor replacement on the Bmw 1500 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 Bmw 1500
On Bmw 1500 vehicles, the turbo boost solenoid and the MAP sensor feed into the same diagnostic path. P1629 caused by a faulty boost solenoid is sometimes charged to the customer as a MAP sensor replacement, doubling unnecessary parts spend.
DIY Repair Guide: P1629 on Bmw 1500
Battery terminal cleaning on the Bmw 1500 is a 5-minute job that resolves a surprising number of P1629 intermittents. Use a wire brush and a bicarbonate of soda solution to clean corrosion, then apply a thin coat of petroleum jelly to the terminals after refitting.
Preventing P1629 on the Bmw 1500
After any fuel system repair on the Bmw 1500, always perform a fuel-trim reset and adaptation drive. Skipping this step leaves the ECU operating on pre-repair learned values, which can generate false P1629 alerts for weeks after the fix.
Frequently Asked Questions — Bmw 1500 P1629
A: Simple fixes like a purge valve or gas cap replacement take under an hour. Sensor replacements typically require 1–2 hours of shop time. More involved repairs like VVT actuators or catalytic converters may require a full day or more.