SureTrack Community Fix: Audi Sensor Resistance

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This fix illustrates the power of the SureTrack community to quickly help a fellow tech solve a problem. A SureTrack community member had a 2010 Audi A6 in the shop with a check engine light on. They posed the question to the community, and with the help of fellow community members, they were able to resolve the issue quickly.

The following Community Fix summarizes the interaction between members of the community that led to the solution.

Vehicle
2010 Audi A6 2.0 Diesel

Title
4914, P0472, P2002, P2453, Replaced Exhaust Pressure Differential Sensor

Complaint
The customer states the check engine light is on.

Diagnostic Steps Performed/Parts Replaced
Connected a scan tool and found codes: 4914 – Diesel Particle Filter; Differential Pressure Sensor: Implausible Signal – Lower Limit Exceeded; P0472 – Exhaust Pressure Sensor “A” Circuit Low; P2002 – Diesel Particulate Filter Efficiency Below Threshold Bank 1; P2453 – Diesel Particulate Filter Pressure Sensor “A” Circuit Range/Performance. At idle, used the scan tool to monitor live data and found the exhaust pressure differential sensor signal parameter was erratic.

Using a lab scope, back probed the exhaust pressure differential sensor signal circuit at the control module and found the signal parameter was erratic, which indicated there was a fault in the sensor or circuitry. Used a multimeter to check for the presence of a short or open in the exhaust pressure differential sensor wiring harness and found there were no shorts or opens present.

Disconnected the exhaust pressure differential sensor connector, visually inspected the connector and terminals and found no obvious signs of damage. Visually inspected the exhaust pressure differential sensor pipe and found no obvious signs of damage. Used the multimeter to measure the resistance of the exhaust pressure differential sensor and found the measured resistance was not within specifications.

Cause
The results of these tests verified the exhaust pressure differential sensor was faulty.

Correction
Replaced the exhaust pressure differential sensor, cleared codes, performed a road test and verified the vehicle operated properly. The check engine light did not illuminate and no fault codes returned.

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