Test point 14
Speed sensor
(transmission) The sensor transmits the transmission speed. ECU compares it to the wheel speed.
Fault code 36
Tlptronic warning lamp comes on, transmission is in emergency mode.
Possible faults: Open circuit, short to ground, short to positive, loose connection
Note:
Check with Tester 9288 (actual values). Store fault as of engine speed = 2800 rpm
1) Pull connector off ECU
a) Measure resistance between pin 2 and pin 38. Nominal value approx. 350 Ohms b) Check that pin 2 und pin 38 are free from shorts to ground. - Check o.k.: ECU faulty
2) Also pull off connector from transmission. Check for continuity at ECU connector pin 2 to pin A Pin 38 to pin F
Short to ground pin 2 und pin 38 to pin 7 (ground)
Pin 2 und pin 38 to pin 20 (screening)
Short to positive pin 2 und pin 38 to pin 1 (positive)
Note:
If it is to be assumed that intermittent faults linked to the output speed occur, the screening connection at pin 20 should be checked after opening the connector housing.
Wiring o.k.: Check sensor and wiring in transmission
Possible transmission faults: Oil strainer clogged, air intake if oil starvation occurs etc., power transmission interrupted.
Fault, Fault code Possible Causes, Elimination, Remarks
Test point 15 If a fault occurs, a replacement value = 60' C Is assumed.
Transmission Possible faults: Open circuit, short to ground, short to positive, temperature sensor corrupted signal
Fault code 37 Note:
Existing faults are stored only when the engine is running.
1) Check temperature with Tester 9288 (actual values)
2) Pull connector off ECU
Check resistance between pin 46 and pin 44 Nominal value approx. 1.00 k£2/20' C
Check wiring. Check o.k.: ECU faulty Figs. 1, 9 Note:
If the display
„Temperature sensor short to positive"
and/or
„Transv. acceleration sensor short to positive"
appears, this may be due to a faulty control unit.
1. Remove short circuit
2. Replace control unit.
Fault, Fault code
Possible Causes, Elimination, Remarks
Test point 16
Selector lever switch/transmission
Fault code 38
Tiptronic warning lamp comes on, transmission is in emergency mode.
Specification: Engine may be started in P or N positions only
Actual status: Engine may also be started in other selector lever positions except P and N Possible faults: Open circuit, short to ground, short to positive
Start possible, except P and N
1) Check adjustment of bowden cable to position switch.
- If required, run electrical test as described under Test point 14, item 4
- No start possible?
2) Pull off start relay R 61 in Central Electrical System
- Ground must be present at relay base terminal 85 when the selector lever is set to P or N.
- Ground present: Check start relay or ignition lock and related wiring
- No ground: Check position switch and wiring to start relay
3) Check position switch as described under Test point 14, item 4
- Position switch o.k. Check continuity:
a) Position switch pin 6 to Central Electrical System (start relay).
b) Junction 40 pin 10 to DME connector pin 42
- Wiring o.k. Transmission-based starting requirements are met.
Test point 17
Control unit faulty
Fault code 42
Tiptronic warning lamp comes on, transmission is in emergency mode.
Replace control unit
Test point 18
Control unit faulty
Fault code 43
Tiptronic warning lamp comes on, transmission is in emergency mode.
Replace control unit
Fault, Fault code
Possible Causes, Elimination, Remarks
Test point 19
Control unit faulty
Fault code 44
Tiptronic warning lamp comes on, transmission Is In emergency mode.
Replace control unit
Test point 20 - 21
Tiptronic warning lamp comes on, transmission is In emergency mode.
Possible faults: Corrupted rpm signal, from output or engine or output/engine rpm relationship
Downshift fault/ rev. limiter Fault code 45, 46
Faulty transmission (clutch slips)
1) Check drive rpm sensor, Test point 14
2) Check transmission
Test point 22 Manual program switch
Fault code 51
No manual program possible.
Detectable faults: Short to ground
1) Check operation with Tester 9288 (Input signals)
2) Pull connector off ECU. Check ground at pin 26.
Check connection from ECU/pin 48 to selector lever switch/pin 3 Connection o.k. Exchange selector lever switch unit Switch and connection o.k.: ECU faulty Figs. 1, 6, 8
2) Pull connector off ECU Check ground at pin 26
Check connection from ECU/pin 10 to selector lever switch/pin 2 (upshift) or connection from ECU/pin 29 to selector lever switch/pin 1 (downshift).
Connection o.k. Replace selector lever switch unit Switch and connection o.k., ECU faulty Figs. 1, 8
Test point 23 Tip-switch up/down shifting
Fault code 52
No manual program possible.
Detectable faults: Short to ground
1) Check operation with Tester 9288 (Input signals)
Fault, Fault code
Possible Causes, Elimination, Remarks
Test point 24 Kick-down switch
Fault code 53
No kickdown shift.
Detectable faults: Short to ground
1a) Acoustical check of switch b) Check operation with Tester 9288 (Input signals - Test)
2) Remove and check kick-down switch (Note: Adjust switch after replacement)
3) Pull connector off ECU.
Check connection of ECU pin 30 to kick-down switch pin 2. Check o.k.: ECU faulty Figs. 1, 12
1) Check sensor with Tester 9288 (actual values)
(Nominal value around 0 g with vehicle on level surface. Sensor can be checked by raising the vehicle on one side).
2) Remove connector from sensor.
Check sensor supply (5 V) to pin 3 and ground at pin 1.
3) Check wiring according to wiring diagram Check continuity from pin 45/ECU to pin 3/sensor Pin 40/ECU to pin 2/sensor
Pin 44/ECU to pin 1/sensor
Short to ground at pin 2 und pin 3/sensor to pin 7/ECU (ground)
Short to positive: Pins 1, 2 and 3/sensor to pin 1/ECU (positive)
Check ground connection of pin 44/ECU
Wiring o.k.: Replace sensor
Fault persists: ECU faulty
Test point 25 Transverse acceleration sensor Fault code 54
Upshifting in curves is not prevented.
Detectable faults: Open circuit/short to ground, short to positive
Fault, Fault code
Possible Causes, Elimination, Remarks
Test point 26 Speed signal 1 of ABS
Fault code 55
Upshifting Is not prevented, no manual program
Detectable faults: Open circuit/short to ground/short to positive
2) Check signal with Tester 9288, raising the vehicle and rotating right-hand front wheel manually.
3) Check wiring according to wiring diagram. Check for continuity: Pin 12/ECU to ABS-SG/pin 23 Short to ground: Pin 12 to pin 7/ECU (ground) Short to positive: Pin 12 to pin 1/ECU (positive)
4) Check signal with oscilloscope (ECU connector pin 12) (Ignition on)
Speed signal
Signal present: ECU faulty No signal: ABS faulty Figs. 1, 3
Test point 27 Combi-instrument input
(Display as of M-program) Fault code 56
No diagnosis possible.
Detectable faults: Open circuit/short to ground, short to positive
1) Turn manual program on and off
Check display on instrument
2) Pull off ECU connector. Connect pin 13 to ground. Display o.k.: ECU faulty
3) Check wiring of ECU pin 13 to speedo pin 9. Wiring o.k. Speedometer faulty
Fault, Fault code
Possible Causes, Elimination, Remarks
Test point 28 Oil cooler blower relay
Fault code 57
Detectable faults: Short to positive
1) Turn cooler blower on and off using Tester 9288. (Drive links) Acoustical check
2) Check fuse No. 2 (Central Electrical System)
3) Disconnect oil cooler relay R 04. Shunt terminals 87 and 30 on relay base. Blower runs: Relay faulty
Blower does not run: Check blower
4) Check connection of ECU/pin 49 to relay base/terminal 85. (Observe connection to A/C control unit).
Wiring o.k.: ECU faulty
Test point 29
Switch R-poshion
Fault code 59
Tiptronic warning lamp comes on, transmission is in emergency mode.
Possible faults: Open circuit, short to ground, signal implausible
1) Ground must be present at pin 41 when the selector lever is set to the P and R positions. (N is possible due to overlaps)
- No ground: Check wiring from ECU connector pin 41 to position switch connector pin 8.
- Wiring o.k. Check position switch as described under Test point 14, item 4.
Fault, Fault code Possible Causes, Elimination, Remarks
Test point 30 No diagnosis possible.
Reverse light relay Detectable faults: Open circuit/short to ground, short to positive
Fault code 60 ^ Trigger reverse light relay with Tester 9288 (Drive links). The relay and the reverse lights must come on and go off in two-second intervals. (Acoustical check. Relay is located on the left-hand side behind the instruments).
2) Disconnect fog light relay R 31 (Central Electrical System). (Note: Both R 31 and RFL relay are supplied via Si 14 and R 01.)
- Check voltage at terminal 30 of relay base.
- No voltage: Check fuse 14 and relay R 01 (Central Electrical System).
3) Pull connector off ECU.
Short-circuit pin 25 to ground (pin 7).
Does reverse light relay pick up?
ECU faulty
4) Pull off reverse light relay.
Check voltage at terminal 30 of relay base.
Check connection of ECU/pin 25 to relay base/terminal 85.
Wiring o.k.: Relay faulty
911 Carrera 2
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