P1640 – OBD-II DTC

OBD-II DTC P1640 – Tire / Axle Ratio Out of Acceptable Range

DTC P1640 meaning

DTC P1640 indicates that the tire or axle ratio is out of the acceptable range as determined by the vehicle’s onboard diagnostic system. This code is triggered when the powertrain control module (PCM) detects a discrepancy between the expected tire or axle ratio and the actual ratio being reported by the vehicle’s sensors. This can affect the vehicle’s performance, fuel efficiency, and overall drivability.

DTC P1640 symptoms

Common symptoms associated with DTC P1640 may include:

• Illuminated check engine light
• Inaccurate speedometer readings
• Unusual transmission behavior, such as harsh shifting
• Decreased fuel efficiency
• Potential loss of traction control or stability control features

DTC P1640 causes

Several factors can lead to the triggering of DTC P1640, including:

• Incorrect tire size or type installed on the vehicle
• Faulty wheel speed sensors
• Malfunctioning PCM or software issues
• Worn or damaged axle components
• Improperly calibrated or replaced differential gears

DTC P1640 seriousness

DTC P1640 can be considered a moderate to serious issue. While it may not cause immediate catastrophic failure, it can lead to significant drivability problems and may affect safety features such as traction control. Ignoring this code can result in further damage to the vehicle’s drivetrain and reduced fuel efficiency.

How to diagnose DTC P1640

To diagnose DTC P1640, follow these steps:

1. Use an OBD-II scanner to confirm the presence of the P1640 code.
2. Check for any additional trouble codes that may provide more context.
3. Inspect the vehicle’s tire size and ensure it matches the manufacturer’s specifications.
4. Examine the wheel speed sensors for damage or disconnection.
5. Test the PCM for proper operation and software updates.
6. Verify the axle and differential components for wear or damage.

How to fix DTC P1640 step-by-step instructions

To fix DTC P1640, follow these steps:

1. Correct any tire size discrepancies by replacing tires with the correct size.
2. Replace or repair any faulty wheel speed sensors.
3. Update or reprogram the PCM if necessary.
4. Inspect and replace worn or damaged axle components.
5. Ensure that differential gears are properly calibrated and installed.
6. Clear the DTC using an OBD-II scanner and test drive the vehicle to see if the code returns.

How to erase DTC P1640

To erase DTC P1640, follow these steps:

1. Connect an OBD-II scanner to the vehicle’s diagnostic port.
2. Turn on the ignition without starting the engine.
3. Navigate to the “Erase Codes” or “Clear Codes” option on the scanner.
4. Confirm the action to clear the trouble codes.
5. Disconnect the scanner and start the vehicle to ensure the code does not return.

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