Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
The car has a sensor that listens for unusual engine noises. This code means that the sensor for the sixth cylinder is having trouble working properly.
The engine control module (ECM) has detected a problem with the signal from the knock sensor for cylinder 6.
The P135E code indicates an issue with the circuit associated with the knock sensor for cylinder 6. This sensor detects vibrations caused by engine knocking, which can be harmful if not addressed. The ECM uses this information to adjust engine timing and prevent damage.
• Check Engine Light on
• Engine knocking noise
• Reduced engine performance
• Poor fuel economy
• Faulty knock sensor
• Wiring issues such as short or open circuits
• Poor electrical connections
• Faulty ECM
ECM: Engine Control Module
Knock Sensor: A device that detects engine knocking or pinging
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connections to the knock sensor.
• Test the knock sensor for proper operation.
• Check the ECM for faults.
• Replace the faulty knock sensor.
• Repair or replace damaged wiring or connectors.
• Reprogram or replace the ECM if necessary.
• OBD-II scanner
• Multimeter
• Socket set
$150 - $400
Moderate
• BMW 3 Series
• BMW 5 Series
• BMW X5
• Regular maintenance checks
• Ensure proper engine tuning
• Use high-quality fuel
Sensor Issue
• Avoid aggressive driving until repaired.
• Have the vehicle inspected by a professional.
Check with the vehicle manufacturer for specific warranty coverage on engine sensors.
This code is relatively common in vehicles with advanced engine management systems that use multiple knock sensors.
Moderate – Addressing this issue promptly can prevent engine damage.
Ignoring this code can lead to engine damage, which may not be covered under warranty if neglected.
• Engine running at operating temperature
• Vehicle driven under various load conditions
The knock sensor for cylinder 6 is typically located on the engine block, near the cylinder.
Q: Can I drive with a P135E code?
A: It's not recommended to drive for extended periods with this code, as it can lead to engine damage.
Q: How does a knock sensor work?
A: A knock sensor detects vibrations caused by engine knocking and sends signals to the ECM to adjust timing.
High-End · Full-system diagnostics
A full-system bidirectional platform aimed at advanced DIY users and professional diagnostic workflows.
Network faults often require full-system access instead of a generic code reader alone.
View on Amazon
Universal · Digital multimeter
A solid entry-level multimeter for voltage, continuity, resistance, and basic electrical troubleshooting.
Helpful for checking voltage drops, grounds, and basic circuit health when modules are not communicating.
View on Amazon
Universal · Wire connectors and repair kit
Useful when diagnosis points toward damaged wiring, corroded terminals, or connector repairs.
Useful if diagnosis points toward damaged connectors, wiring, or terminal repairs.
View on AmazonThese are optional diagnostic tools, not guaranteed fixes. As an Amazon Associate I earn from qualifying purchases.