P1635 Mercury Code - Tire / Axle Ratio Out of Acceptable Range
Quick Answer
The P1635 diagnostic trouble code for Mercury vehicles indicates that the tire or axle ratio is out of an acceptable range. Common causes include Incorrect tire size or type installed on the vehicle, Faulty axle ratio sensor, Transmission or drivetrain issues. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P1635 Mercury indicates Tire / Axle Ratio Out of Acceptable Range.
- Common causes
- Common causes include Incorrect tire size or type installed on the vehicle, Faulty axle ratio sensor, Transmission or drivetrain issues.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
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Code P1635 Mercury Description
The P1635 diagnostic trouble code for Mercury vehicles indicates that the tire or axle ratio is out of an acceptable range. This issue can have a significant impact on the vehicle's performance and overall drivability. The tire or axle ratio is a crucial factor in the vehicle's transmission and drivetrain system, affecting the power delivery to the wheels and the overall efficiency of the vehicle. When this ratio is out of range, it can lead to issues such as poor acceleration, decreased fuel efficiency, and potential drivability issues.
Common Causes of P1635 Mercury
- Incorrect tire size or type installed on the vehicle
- Faulty axle ratio sensor
- Transmission or drivetrain issues
- Wiring or electrical problems in the axle ratio sensor circuit
- Software or programming issues in the vehicle's control module
Symptoms of P1635 Mercury
- Decreased acceleration or sluggish response
- Poor fuel efficiency
- Difficulty shifting gears
- Unusual noises coming from the drivetrain
- Illumination of the Check Engine Light
How to Fix P1635 Mercury
- Inspect and verify the correct tire size and type for the vehicle
- Check the axle ratio sensor for proper operation and replace if necessary
- Diagnose and repair any transmission or drivetrain issues
- Inspect and repair any wiring or electrical problems in the axle ratio sensor circuit
- Update or reprogram the vehicle's control module if needed
Cost to Fix P1635 Mercury
The typical repair costs for addressing a P1635 code on a Mercury vehicle can range from $200 to $500, depending on the specific cause of the issue and the required repairs. This estimate includes parts and labor, but actual costs can vary based on factors such as location, vehicle make and model, and the complexity of the repair. It is recommended to consult with a qualified mechanic or auto repair shop for a more accurate cost estimate based on your specific circumstances.
Tech Notes for P1635 Mercury
After a new Powertrain Control Module (PCM) has been installed, the Vehicle Identification (VID) block has to be programmed into the PCM.
There is a Factory Service Bulletin for the following Mercury models:
2008-2011 Mercury Grand Marquis / Marauder
2008-2011 Mercury Mariner
2008-2011 Mercury Milan
2008-2009 Mercury Montego
2008-2010 Mercury Mountaineer
2008-2009 Mercury Sable
Mercury Factory Service Bulletin OBDII Code P1635
There is a Factory Service Bulletin for the 2002 Mercury Mountaineer:
2002 Mercury Mountaineer Factory Service Bulletin OBDII Code P1635
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Frequently Asked Questions about P1635 Mercury Code
What does the OBDII code P1635 mean for a Mercury vehicle?
Code P1635 indicates that the Tire/Axle Ratio is out of the acceptable range, meaning the vehicle's tire size or axle configuration may not match factory settings.
What are the common symptoms of code P1635 in Mercury vehicles?
Symptoms include inaccurate speedometer readings, reduced fuel efficiency, and potential transmission shifting issues.
What causes the P1635 code on Mercury vehicles?
The code is typically caused by incorrect tire sizes, changes to the axle ratio, or a malfunction in the Powertrain Control Module (PCM).
Can aftermarket modifications trigger the P1635 code?
Yes, installing non-standard tire sizes or changing the axle ratio without reprogramming the PCM can trigger this code.
How is the P1635 code diagnosed?
A technician will verify the tire size and axle ratio, inspect the PCM for software errors, and check for wiring issues related to the speed sensor.
How do you fix the P1635 code in a Mercury vehicle?
Repairs may include recalibrating the PCM, replacing tires with factory-specified sizes, or correcting axle ratio mismatches.
Can driving with the P1635 code cause damage to the vehicle?
While it may not cause immediate damage, prolonged driving with this code can lead to transmission wear and reduced performance.
Does the P1635 code affect the vehicle's speedometer?
Yes, it can cause inaccurate speedometer readings due to mismatched tire or axle ratios impacting the speed calculation.
Can a faulty speed sensor cause the P1635 code?
While less common, a malfunctioning speed sensor can contribute to this code by sending incorrect data to the PCM.
Is reprogramming the PCM always required to fix the P1635 code?
Reprogramming is necessary if tire or axle modifications were made, but it may not be required if the issue is related to sensor or wiring faults.
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