AutoCodes – Lincoln – P1635 Lincoln

P1635 Lincoln Code - Tire / Axle Ratio Out of Acceptable Range

Quick Answer

The All-Wheel Drive (AWD) system continuously monitors vehicle conditions and automatically adjusts the torque distribution between the front and rear wheels. Common causes include Incorrect tire size, Incorrect axle ratio, Incorrect Vehicle ID block configuration parameters. 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 Lincoln indicates Tire / Axle Ratio Out of Acceptable Range.
Common causes: Common causes include Incorrect tire size, Incorrect axle ratio, Incorrect Vehicle ID block configuration parameters.
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 Popularity 5,825

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Apr 09, 2023

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
Comments
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Code P1635 Lincoln Description

The All-Wheel Drive (AWD) system continuously monitors vehicle conditions and automatically adjusts the torque distribution between the front and rear wheels. During normal operation, most of the torque is sent to the front wheels. If a wheel slip between the front and rear wheels is detected or the vehicle is under heavy acceleration, the AWD system increases torque to the rear wheels. When the 4X4 control module detects inappropriate mini spare or road wheels/tires (greater than 7% across the front and rear axle or 14% at one wheel) installed, this Diagnostic Trouble Code (DTC) is set.

OBDII Code P1635 Lincoln - Tire / Axle Ratio Out of Acceptable Range - AutoCodes.com — P1635 Lincoln Code - Tire / Axle Ratio Out of Acceptable Range

What does this mean?

What are the Possible Causes of the DTC P1635 Lincoln?

Incorrect tire size
Incorrect axle ratio
Incorrect Vehicle ID block configuration parameters

How to Fix the DTC P1635 Lincoln?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

On some Lincoln models, the Powertrain Control Module (PCM) DTC P1635 indicates that the tire size or axle ratio programmed into the PCM is not correct for the PCM calibration present in the PCM. This DTC can be caused by a modified PCM calibration, or a tire size or axle ratio programmed into the PCM that does not match the vehicle's build information.

After a new Powertrain Control Module (PCM) has been installed, the Vehicle Identification (VID) block must be programmed into the PCM.

There is a Factory Service Bulletin for the following Lincoln models:
2017-2019 Lincoln Continental
2008 Lincoln Mark LT
2015-2019 Lincoln MKC
2009-2016 Lincoln MKS
2010-2019 Lincoln MKT
2008-2018 Lincoln MKX
2008-2019 Lincoln MKZ
2019 Lincoln Nautilus
2008-2019 Lincoln Navigator
2008-2011 Lincoln Town Car
Lincoln Factory Service Bulletin OBDII Code P1635

There is a Factory Service Bulletin for some 1999-2022 Lincoln models:
Lincoln Factory Service Bulletin OBDII Code P1635

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1635 Lincoln code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.