Chevrolet Trailblazer 2 P1629 Engine Trouble Code
What is Chevrolet Trailblazer 2 P1629?
When Chevrolet Trailblazer 2 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 Chevrolet Trailblazer 2
In cold climates, Chevrolet Trailblazer 2 vehicles frequently log P1629 during the first winter of ownership. Condensation inside the throttle body creates a temporary short circuit in the position sensor wiring, which clears once the engine warms up — but the fault code remains stored.
Code Information
| Code Type: | OBD-II Powertrain (P) Trouble Code |
| System: | Powertrain |
| Vehicle: | Chevrolet Trailblazer 2 |
| Brand: | Chevrolet |
| Model: | Trailblazer 2 |
| Code: | P1629 |
P1629 Chevrolet Trailblazer 2 Symptoms
Check Engine Light
Illuminated Chevrolet Trailblazer 2 dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration on the Chevrolet Trailblazer 2
Starting Problems
Difficulty starting the engine
Poor Fuel Economy
Increased fuel consumption on the Chevrolet Trailblazer 2
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 Chevrolet Trailblazer 2 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:
Firing order is engineered to minimise vibration. Altering firing order results in mistimed ignition and poor engine operation. Consult vehicle-specific repair manual for correct firing order.
Technical Notes:
P1629 on electronically controlled automatic transmissions relates to shift solenoid operation. The solenoid actuates hydraulic circuits controlling clutches or bands for gear changes.
Chevrolet Trailblazer 2 P1629 Repair Cost
MAF sensor replacement on the Chevrolet Trailblazer 2 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 Chevrolet Trailblazer 2
When Chevrolet Trailblazer 2 presents P1629 with a concurrent coolant temperature DTC, technicians sometimes replace the thermostat rather than the coolant temperature sensor (CTS). The CTS is a $15–$25 component; the thermostat job carries 1–2 hours of additional labour.
DIY Repair Guide: P1629 on Chevrolet Trailblazer 2
The Chevrolet Trailblazer 2 EVAP purge solenoid valve is accessible without lifting the vehicle — it is mounted on the intake manifold and secured by a single bolt and a vacuum hose clip. DIY replacement is rated 1/5 difficulty and takes approximately 20 minutes.
Preventing P1629 on the Chevrolet Trailblazer 2
The Chevrolet Trailblazer 2 heat shield over the exhaust manifold protects the nearby sensor wiring from radiant heat damage. Inspect it for cracks or displacement at every brake service. A $15 replacement shield can prevent $300+ wiring loom repairs.
Frequently Asked Questions — Chevrolet Trailblazer 2 P1629
A: P1629 is a standardised OBD-II code that can appear on any make and model. However, the specific components and circuits that trigger this code, and the repair procedures involved, vary significantly between vehicles. The information on this page is focused on the Chevrolet Trailblazer 2.