[Repair Case] 2014 Audi A7 multiple fault lights suddenly light up while driving.

Posted by Tony Brown on

Model: 2014 Audi A7 Coupe.

Driving mileage: 37282miles.

 

Issue: Multiple fault lights suddenly light up during driving, with ABS, tire pressure monitoring and air suspension all illuminated. The fault remains after the car is turned off and restarted.

 

Diagnosis: First, connect to VCDS and enter 03 detection, the fault code is 0365 of the right front wheel speed sensor, the fault code is shown in Figure 1.

 

Figure 1

Turn the right front wheel once the wheel is off the ground, and the wheel speed as well as forward and backward status can be displayed normally in the data block. The sensor appears to be dirty or in poor contact at first. Clear the fault code and put the car through its paces after handling. After driving approximately 2 miles, the issue resurfaced, and the fault code was identical to the previous one.

 

Restructure the troubleshooting procedure. This error is caused by a failure of an electrical circuit rather than by faulty signals, which is common. The crucial line maintenance measures appear to have been overlooked. The right front wheel of this car has a reasonably simple line connection. There are two black and two green sensors on the sensor. The pins are attached to the ABS control unit's 41st and 26th pins, respectively. Figure 2 depicts the circuit diagram.

 

Figure 2

To remedy a short circuit fault, the author unplugs the ABS control unit, then uses jumpers to short the sensor's two pins, then uses a multimeter to test the resistance between the 41 and 26 pins of the control unit, and finally starts the engine. 0.3 is the resistance. The resistance suddenly becomes limitless after numerous turns of the steering wheel. There appears to be a serious issue with the circuit.

 

Inquiring about ETKA, it was found that the right front wheel harness was supplied separately, as shown in Figure 3.

Figure 3

The wiring harness is folded into a U shape for this car's wiring demands, and the rubber sleeve is secured to the lug. The electrical harness is tugged once every time the wheel is spun, resulting in fatigue damage over time. Pull the ABS wire harness along when a malfunction develops. The line has been vacantly attached at the root of the fixed lug, the copper core is damaged, and the rubber sheath is intact. Figure 3 shows the shattered spot after cutting with a knife.

 

Troubleshooting: Replace the wiring harness, adjust the position of the lugs, and after reasonable wiring, the road test is about 30 kilometers in various road conditions, and the fault is eliminated.


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