P1700
Symptom: The "CHECK ACS" lamp is on. The system's emergency "Limp Home" program has been activated. Owing to failure of the gear selector position sensor, the system cannot obtain information on the engaged gear. The engine can be started and the car can be driven off in all gears. Declutching also takes place when the driver grasps the gear lever and presses it harder into the gear that is already engaged.
Gear selector position sensor, function faulty
Fault symptom
The "CHECK ACS" lamp is on. The system's emergency "Limp Home" program has been activated. Owing to failure of the gear selector position sensor, the system cannot obtain information on the engaged gear. The engine can be started and the car can be driven off in all gears. Declutching also takes place when the driver grasps the gear lever and presses it harder into the gear that is already engaged.
Condition
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Gear position - lengthwise <0.2 V or >4.8 V
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Gear position - crosswise <0.2 V or >4.8 V
Warning
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If the car has to be driven with a defective or disconnected gear selector position sensor, the gear lever must always be put into neutral before the engine is started.
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Diagnostic procedure
1 Check the sensor's ground connection and power supply
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Unplug the gear selector position sensor's four-pin connector, located next to the clutch actuator unit.
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Turn the ignition switch to the ON position. Take readings on the female connector between
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pin 1 and Batt-, about 5 V
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Are the readings correct?
Continue with point 2.
Repair or replace the lead in question and proceed to point 3.
2 Check the control module sensor inputs
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Unplug the gear selector position sensor's four-pin connector, located next to the clutch actuator unit.
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Turn the ignition switch to the ON position.
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Connect the Scan tool diagnostics instrument and read off the lengthwise and crosswise gear position values. The Scan tool diagnostics instrument should show 0.0-0.1 V.
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Connect jumper leads in the position sensor's connector across pins 1 and 2 and across pins 1 and 3. The Scan tool diagnostics instrument should show a reading of 4.9-5.0 V.
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All readings OK?
Change the gear selector position sensor, see
, and continue with point 3. Remember that the gear selector position sensor is an extremely sensitive piece of equipment and can easily be damaged when fitted in place, so follow the fitting instructions carefully. Finish off by calibrating the gear positions by means of the Scan tool diagnostics instrument.
Repair or replace the lead in question and proceed to point 3.
3 Final check
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Clear the diagnostic trouble code.
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Perform a drive cycle by driving the car at varying engine rpm and loads for 5 minutes. Change gear frequently and use all the gears.
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Check whether the diagnostic trouble code has recurred.
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Has the diagnostic trouble code recurred?
Continue as described in the section "Before replacing a control module", see
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The steps taken to rectify the fault were correct.
