Ford Expedition P1629 Engine Trouble Code
What is Ford Expedition P1629?
Ford Expedition P1629 indicates potential catalytic converter failure. If completely failed, your vehicle may not run properly and fuel economy will suffer significantly. Average replacement cost is $2,000–$2,140. This repair requires professional service and should not be delayed.
P1629 on the Ford Expedition
The Ford Expedition features a sequential multi-port fuel injection (SMFI) system where injector timing is tightly synchronised with the crankshaft signal. Wear on the crankshaft reluctor ring teeth produces signal dropout events that accumulate and eventually trigger P1629.
Code Information
| Code Type: | OBD-II Powertrain (P) Trouble Code |
| System: | Powertrain |
| Vehicle: | Ford Expedition |
| Brand: | Ford |
| Model: | Expedition |
| Code: | P1629 |
P1629 Ford Expedition Symptoms
Check Engine Light
Illuminated Ford Expedition dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration on the Ford Expedition
Starting Problems
Difficulty starting the engine
Poor Fuel Economy
Increased fuel consumption on the Ford Expedition
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 Ford Expedition P1629
Diagnostic Steps:
The catalytic converter has oxygen sensors before and after it. When warm and in closed-loop mode, the upstream O2 sensor reading should fluctuate, while downstream should remain steady.
Repair Solution:
VSS concerns may stem from noisy input signals caused by RFI/EMI from ignition wires, charging circuits, or aftermarket equipment. Verify VSS reads 0 mph when transmission is in Park.
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.
Ford Expedition P1629 Repair Cost
PCV system overhaul on the Ford Expedition — which resolves oil-mist contamination of the MAF sensor — costs $100–$200. The MAF sensor should be cleaned ($15–$25 DIY) or replaced ($80–$150) at the same time to ensure accurate fuelling after the fix.
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 Ford Expedition
Fuel injector replacement is over-prescribed on the Ford Expedition for P1629 when the actual fault is a weak fuel pump. Low fuel rail pressure causes lean misfire that looks identical to injector failure in static scan data without a live fuel pressure test.
DIY Repair Guide: P1629 on Ford Expedition
For the mechanically confident Ford Expedition owner, a DIY MAF sensor clean is a rewarding first step for P1629. Use a dedicated MAF sensor cleaner spray — not brake cleaner, which damages the sensing element — and allow the sensor to dry for 30 minutes before reinstallation.
Preventing P1629 on the Ford Expedition
Ensure the Ford Expedition oil cap and dipstick tube seal are airtight. Even a small crank-case vacuum leak can cause the PCM to log P1629 and, over time, allows moisture-laden air to degrade the engine oil faster than the scheduled service interval.
Frequently Asked Questions — Ford Expedition P1629
A: If your Ford Expedition is within the factory powertrain warranty period (typically 3–5 years or 60,000–100,000 miles depending on region and generation), P1629 repairs caused by component defects should be covered. Bring your service history to the dealer appointment.