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Code P16B4

Symptoms

• Cruise control not functioning

• Warning light on the dashboard

• Intermittent cruise control operation

Common Causes

• Faulty control module

• Software glitch in the control module

• Wiring issues or poor connections

Glossary

Control Module: An electronic device that manages various functions in the vehicle.

Dynamic Cruise Control: A system that automatically adjusts the vehicle's speed to maintain a safe distance from the car ahead.

Related Codes

• P16B5

• P16B6

Laymans terms

This code means that the car's computer is having trouble checking if the cruise control system is working properly.

Explanation

The P16B4 code indicates a fault in the self-test process of the control module responsible for monitoring the Dynamic Cruise Control system.

Technical description

The control module performs a self-test to ensure all systems, including the Dynamic Cruise Control (DCC), are functioning correctly. If it detects an issue during this self-test, it triggers the P16B4 code.

Diagnosis steps

• Check for any other related codes.

• Inspect wiring and connections to the control module.

• Perform a software update or reset on the control module.

Repair procedures

• Repair or replace faulty wiring or connections.

• Update or reflash the control module software.

• Replace the control module if necessary.

Tools required

• OBD-II scanner

• Multimeter

• Diagnostic software tool

Estimated repair cost

$150 - $600

Difficulty level

Moderate

Commonly affected vehicles

• Toyota Camry

• Honda Accord

• Ford Fusion

Preventive measures

• Regular software updates

• Routine maintenance checks

• Ensure proper connections and wiring integrity

Error code type

Control Module Issue

User experience recommendations

• Have your vehicle checked by a professional if the cruise control is not working.

• Regularly update your vehicle's software at the dealership.

Warranty information

Control module issues may be covered under the vehicle's powertrain or emissions warranty.

Historical data

This code has been reported in vehicles with advanced cruise control systems, often related to software issues.

Urgency level

Moderate – While the vehicle may still be drivable, the cruise control system may not function properly.

Legal and safety notice

Driving without a functional cruise control system can affect vehicle handling and safety on long trips.

Testing conditions

• Vehicle parked and engine off

• Access to diagnostic tools

Component location

The control module is typically located under the dashboard or near the engine compartment.

FAQs

Q: Can I drive my car with a P16B4 code?
A: Yes, but the cruise control may not work, which can be inconvenient on long drives.

Q: Will resetting the code fix the problem?
A: Resetting the code may temporarily clear the warning, but the underlying issue should be diagnosed and repaired.

Last updated: Jun 9, 2026 • Source: internal database
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