Mg 1100 P1629 Engine Trouble Code
What is Mg 1100 P1629?
When Mg 1100 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 Mg 1100
The Mg 1100 ECU flash version prior to the 2.4.1 update has a known calibration bug that can generate spurious P1629 codes under hard deceleration. Verifying the ECU software version is always the first step before any mechanical diagnosis on this model.
Code Information
| Code Type: | OBD-II Powertrain (P) Trouble Code |
| System: | Powertrain |
| Vehicle: | Mg 1100 |
| Brand: | Mg |
| Model: | 1100 |
| Code: | P1629 |
P1629 Mg 1100 Symptoms
Check Engine Light
Illuminated Mg 1100 dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration on the Mg 1100
Starting Problems
Difficulty starting the engine
Poor Fuel Economy
Increased fuel consumption on the Mg 1100
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 Mg 1100 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:
Power steering pressure switch monitors system operation. If pressure changes are not detected after calibrated speed transitions, this DTC sets. Verify PSP switch operation and check for circuit opens or shorts.
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.
Mg 1100 P1629 Repair Cost
Throttle body cleaning and idle relearn on the Mg 1100 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 Mg 1100
Workshop technicians sometimes replace the entire ignition coil assembly on the Mg 1100 when P1629 accompanies a cylinder-specific misfire. In many cases, only the spark plug in the misfiring cylinder has fouled; a $8 plug replaces a $140 coil pack.
DIY Repair Guide: P1629 on Mg 1100
The coolant temperature sensor on the Mg 1100 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 Mg 1100
On the Mg 1100, using a quality fuel system cleaner (added to the fuel tank every 10,000 miles) helps prevent injector deposit build-up that indirectly triggers P1629 through fuel-trim imbalances.
Frequently Asked Questions — Mg 1100 P1629
A: It depends on the severity. If the check-engine light is steady, it is generally safe to drive to a workshop within the next few days. If the light is flashing, pull over safely as soon as possible — a flashing light indicates an active misfire that can cause expensive catalytic converter damage within minutes.