Potentiometer Signal Too High
A A. Diagnostic trouble code (DTC) information
Condition
- Motor 1 controls the seat adjustment forward/backward. If voltage from potentiometer for motor 1 to control module terminal V1 exceeds 4.6 V diagnostic trouble code (DTC) PSL/PSR-112 is set.
Possible source
- Contact resistance in terminals.
- Loose contacts in terminals.
- Defective potentiometer, motor 1.
- Open-circuit in ground lead between control module and potentiometer, motor 1.
- Signal wire between control module and potentiometer for motor 1 short-circuited to battery voltage.
- Supply wire between control module and potentiometer for motor 1 short-circuited to battery voltage.
- Defective control module.
Fault symptom(s)
- Memory activation does not work.
- Fault-tracing begins at AB.
A B. Potentiometer signal too high
AB1: Checking status
- Ignition OFF.
Select scrolling values and read off the value from the potentiometer for motor 1.
Move the seat forward and backward between the seat end positions several times using the control button.
The potentiometer value must not exceed 4.6 V at any time.
If reading is OK:
- AB13
If reading is incorrect:
- AB2
AB2: Checking resistance in circuit to potentiometer
- Ignition OFF.
- Remove seat from car.
- Disconnect black 14-pin connector C.
Connect an ohmmeter between positions C:12 and C:13 on black 14-pin connector (potentiometer side).
The ohmmeter should read approx. 2200 ohm.
If reading is OK:
- AB8
If reading is incorrect:
- AB3
AB3: Checking potentiometer resistance
- Ignition OFF.
- Disconnect the black 14-pin connector.
- Remove potentiometer on motor 1.
Connect an ohmmeter between two outer terminals on the potentiometer.
The ohmmeter should read approx. 2200 ohm.
If reading is OK:
- AB5
If reading is incorrect:
- AB4
AB4: Replace component
Test with new potentiometer. Motors and potentiometers underneath seat, Service and Repair
Then continue with:
- AB11
AB5: Checking potentiometer's ground
- Ignition OFF.
- Disconnect 3-pin connector to potentiometer on motor1.
- Disconnect the black 14-pin connector C.
Connect an ohmmeter between the black 14-pin connector terminal C:12 and the corresponding terminal on the 3-pin connector (brown wire).
The ohmmeter should read approx. 0 ohm.
It reading is OK:
- AB7
If reading is incorrect:
- AB6
AB6: Checking for an open-circuit
Check the brown ground lead between the control module, terminal C:12, and the potentiometer for open-circuit.
Then continue with:
- AB11
AB7: Checking, contact resistance and oxidation
Check the 3-pin connector to the potentiometer on motor 1 for contact resistance and oxidation and take corrective action.
Then continue with:
- AB11
AB8: Checking the supply and signal leads on the potentiometer
- Ignition OFF.
- Disconnect the black 14-pin connector C.
Connect an ohmmeter between supply lead, terminal C:13, and the six supply leads to the motors, terminals C:1-C:6, in the black 14-pin connector on the potentiometer side.
Connect an ohmmeter between signal lead, terminal C:9, and the six supply leads to the motors, terminals C:1-C:6, in the black 14-pin connector on the potentiometer side.
The ohmmeter should read infinite resistance for all readings.
If reading is OK:
- AB10
If reading is incorrect:
- AB9
AB9: Checking for a short-circuit
The measurements show that the signal lead or supply lead to the potentiometer is short-circuited to battery voltage.
Check the red supply lead between terminal C:13, and the potentiometer on motor 1 for short-circuit to supply.
Check the yellow/red supply lead between terminal C:9, and the potentiometer on motor 1 for short-circuit to supply.
Then continue with:
- AB11
AB10: Checking control module and connector C
Potentiometer and cables are fault-free
Check and correct the 14-pin black connector C for contact resistance and oxidation.
Checking wiring and connections. Permanent faults, Component Tests and General Diagnostics
If the fault persists after verification, try a new control module, Service and Repair
Then continue with:
- AB11
AB11: Verification
Hint: After carrying out the repair, check that the fault has been remedied as follows:
- Ignition OFF.
- Reinstall components, connectors etc.
- Connect up seat in car. Wiring up for voltage measurement, Wiring Up For Voltage Measurement
Select scrolling values and read off the value from the potentiometer for motor 1.
Operate the seat forward/backward, running it to the end positions in both directions.
The values indicated for potentiometer 1 must not be more than 4.6 V or less than 0.2 V.
If reading is OK:
- Fault corrected
If reading is incorrect:
- AB12
AB12: Fault-tracing information
The verification result shows that the fault persists.
Do you want to exit fault-tracing?
Yes:
- Fault not corrected
No:
- AB1
AB13: Intermittent fault
Check the black 14-pin connector C and potentiometer connector to motor 1 for loose contacts,contact resistance and oxidation.
Check the ground lead between control module, terminal C:12 (brown lead), and the potentiometer on motor 1 for intermittent open-circuit.
Control the signal and supply leads between the control module and the potentiometer on motor 1, terminal C:9 and C:13, for intermittent short-circuit to supply.
Then continue with:
- AB14
AB14: Fault-tracing information
For intermittent faults fault-tracing is not followed by a verification because the fault is not present at this moment.
Do you want to repeat fault-tracing?
Yes:
- AB1
No:
- Operation done