P1817
Symptom: CHECK GEARBOX warning lamp on.
TCM in Limp-Home mode.
Input RPM. No Signal.
Fault symptoms
CHECK GEARBOX warning lamp on.
TCM in Limp-Home mode.
Conditions
No signal from the input shaft speed sensor when:
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The speed of the car in first gear is higher than 7 km/h.
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The speed of the car in second gear is higher than 13 km/h.
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The speed of the car in third gear is higher than 18 km/h.
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The speed of the car in fourth gear is higher than 26 km/h.
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Selector lever position sensor in position D, 3, 2 or 1.
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Engine speed above 400 rpm
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Diagnostic help
A reading of the input shaft speed can be obtained with the diagnostics instrument.
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Select “
Data Display / Output Control (New)”.
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With the selector lever in position P or N, the diagnostics instrument should show the same rpm as indicated on the tachometer.
Check the wiring
Jiggle the wiring harness at several points and in different directions to reveal intermittent breaks and short circuits in the various leads. Observe the multimeter, test lamp or diagnostic instrument while carrying out this check.
Diagnostic procedure
1 Check the speed sensor ground connection
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Unplug the 2-pin speed sensor connector.
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Connect a test lamp between B+ and pin 2 (green lead) in the 2-pin female connector.
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The test lamp should light up.
All OK?
Continue with step 2.
Rectify the relevant lead and continue with step 3, final check.
2 Check the control module input for input speed.
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Measure the resistance between the two pins in the 2-pin female connector.
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The resistance should be 2.0-2.4 kOhm
All OK?
Change the speed sensor and continue with step 3, final check.
Rectify the relevant lead between speed sensor pin 2 and control module pin 12, and continue with step 3, final check.
3 Final check
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Clear all diagnostic trouble codes in the system.
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Perform a driving cycle:
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Drive the car at varying loads and engine speeds for 5 minutes.
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Evaluate the driving cycle:
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Make sure the trouble code has not recurred.
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Has the trouble code recurred?
Continue with “
Diagnostic procedure before replacing control module
”
The steps taken to rectify the fault were correct.
