DME Diagnosis
Fault Overview
Part 1:
Part 2:
General Test Point
Continuous positive voltage (terminal 30)
Connect voltmeter to control module connector or adapter 9616 (test box) pin 6 (ground) and pin 26.
Display: 12.5 V with ignition "OFF"
Connect voltmeter to pin 6 (ground) and pin 54
Display: 12.5 V with ignition "ON" (connected via DME relay) If there is no display: Check current path according to wiring diagram.
Test point 1
Oxygen sensor heater 2 and oxygen sensor heater 1 ahead of cat. converter
DTC 5, 13
1. Pull off relay (ignition/oxygen sensors) from relay support 2 with the special tool "relay extractor 9235".
Connect ohmmeter to relay base pin 87 and to control module connector pin 30
Ignition "OFF" (pull off one sensor connector in each case) Required measured value: 1 - 15 Ohms
NOTE: Both sensor heaters are connected in parallel.
2. Pull off the sensor connector and connect voltmeter to pin 1 and ground
Ignition "ON"
Display: approx. 12 Volt
If there is no display: Check current path according to wiring diagram.
Test point 2
O2 sensor ahead of cat. conv., cylinders 1 - 3
O2 sensor ahead of cat. conv., cylinders 4 - 6
DTC 10, 18
Oxygen sensor of cylinders 1 - 3
Connect voltmeter to control module connector pin 19 (+) and pin 46 (-).
Ignition "ON"
Display: approx. 450 mV
Start engine. With the engine warm, the voltage fluctuates between approx. 0.1 and 0.9 V.
Oxygen sensor of cylinders 4 - 6 Connect voltmeter to control module connector pin 18 (+) and pin 46 (-).
Ignition "ON"
Display: approx. 450 mV
Start engine. With the engine warm, the voltage fluctuates between approx. 0.1 and 0.9 V.
NOTE: If a fault is stored, there may also be a leak in the intake system. Before replacing the oxygen sensors, check that the oil filler cover and the oil dipstick are seated correctly and check the entire intake system for leaks.
Test point 3
Oxygen sensor ageing ahead of cat. conv., cylinders 1 - 3
Oxygen sensor ageing ahead of cat. conv., cylinders 4 - 6
DTC 15, 16, 21, 22
NOTE: Check whether additional faults are stored in the memory, and remedy these faults first.
1. Erase fault memory.
2. Heat the oxygen sensors (test drive under load, run engine without load at high rpm).
3. Perform test drive.
4. Read out the fault memory and check whether the fault was stored again. If the fault re-appears, the corresponding oxygen sensor must be replaced.
Test point 4
Oxygen sensing range 2 and range 1, cylinders 1 - 3
DTC 26, 27, 28
Fault: Lean limit
Mixture is so rich that the control is at its lean limit.
Fault area:
Fuel pressure too high or injection valve leaks.
Remedy:
1. Check fuel pressure.
2. Check fuel pressure regulator, vacuum connection and fuel return line.
Fault: Rich limit
Mixture is so lean that the control is at its rich limit.
Fault area:
Intake system leaks
Fuel pressure too low
Injection valves fouled
Fuel pump delivery too low
Remedy:
1. Check exhaust system for leaks.
2. Check intake system for leaks.
3. Check fuel pressure.
4. Check fuel pump delivery.
5. Clean injection valves in ultrasound cleaning device or replace.
Test point 5
Engine compartment temperature sensor
DTC 30
Connect ohmmeter to adapter terminal 16 and terminal 34.
The control module connector must be disconnected from the adapter during the measurement.
Display: 2.4 kOhms
Pull off the temperature sensor connector and connect voltmeter to terminal 1 and terminal 2.
Ignition "ON"
Display: approx. 5 V
Test point 6
Idle control at stop
DTC 32
Possible faults:
IACV (idle speed positioner) defective
Intake system leaks
Test point 7
Oxygen sensing range 2 and range 1, cylinders 4 - 6
DTC 34, 35, 36
Fault: Lean limit
Mixture is so rich that the control is at its lean limit.
Fault area:
Fuel pressure too high or injection valve leaks.
Remedy:
1. Check fuel pressure.
2. Check fuel pressure regulator, vacuum connection and fuel return line.
Fault: Rich limit
Mixture is so lean that the control is at its rich limit.
Fault area:
- Intake system leaks
- Fuel pressure too low
- Injection valves fouled
- Fuel pump delivery too low
Remedy:
1. Check exhaust system for leaks.
2. Check intake system for leaks.
3. Check fuel pressure.
4. Check fuel pump delivery.
5. Clean injection valves in ultrasound cleaning device or replace.
Test point 8
Anti-drive-off feature
DTC 39
Possible faults:
1. Transponder (wrong key)
2. DME control module was replaced but not yet reprogrammed with the System Tester.
3. Fault in the alarm system; read out fault memory of the alarm system.
4. Check wire from DME control module pin 88 to alarm control module terminal I/23 for continuity, short to B+ and ground (pin 28).
Test point 9
Misfire detection
DTC 50 - 55, 62 - 68 and 75
1. Measure resistance:
Connect ohmmeter to pin 1 and pin 15 of the ignition coil
Display: 0.7 Ohms
2. Measure voltage:
Pull off ignition coil connector and measure between pin 2 (-) and pin 3 (+)
Ignition "ON"
Display: approx. 12 V
3. Pull spark plug connector off the ignition coil
Measure resistance at the spark plug connector
Display: 2.5 kOhms
Test point 10
Fuel evaporative valve
DTC 98
1. Pull off valve connector and connect voltmeter to pin 2 (+) and engine ground
Ignition "ON"
Display: approx. 12 V
2. Ignition "OFF"
Pull off control module connector
Connect ohmmeter between pin 61 and pin 54
Display: In temperature range between 18 and 28 °C = 22 - 30 Ohms
Test point 11
Control module faulty
DTC 101, 102, 103, 104, 105
If DTC 101, 102, 103 or 105 is displayed, replace the DME control module.
If DTC 104 is displayed, erase the fault memory. Perform a test drive. If DTC 104 is stored again, replace the DME control module.
Test point 12
Supply voltage
DTC 107
Connect voltmeter with control module connector pin 6 and pin 54.
Ignition "ON"
Display: approx. 12.5 V
Test point 13
Continuous positive voltage
DTC 108
Test procedure:
Pull off the control module connector and connect voltmeter with pin 6 (-) and pin 26 (+)
Ignition "OFF"
Display: Battery positive voltage
If there is no display, check the current and ground path according to the wiring diagram.
Test point 14
Reference mark sensor (rpm sender)
DTC 111
Perform test with an oscilloscope.
Connect tester lead with control module connector pin 20 (rpm sender ground) and pin 78 (rpm sender signal).
Start engine. A sinusoidal trace must be visible on the screen. A briefly higher amplitude identifies the reference mark signal.
Test point 15
Hall-effect sensor 1 Hall-effect sensor 2 (only on OBD II vehicles)
DTC 112, 113
1. Connect voltmeter with control module connector pin 53 (+) and pin 34 (-).
Ignition "ON"
Display: approx. 5 V
2. Check Hall signal with an oscilloscope.
Connect oscilloscope with pin 21 for this purpose. Start engine. The following signal must be displayed.
Test point 16
Hot film MAF sensor
DTC 115
Connect voltmeter to control module connector or adapter 9616 (test box) pin 47 (+) and pin 45 (-)
Ignition "ON"
Display: 5 V
Connect voltmeter to control module connector or adapter 9616 (test box)
pin 17 (+) and pin 45 (-)
Ignition "ON"
Display: 1 V
Pull connector off hot film mass air flow sensor
Ignition "ON"
Connect voltmeter to pin 2 (connector side) and engine ground
Display: Battery positive voltage
Test point 17
Throttle potentiometer
DTC 117
Connect voltmeter to control module connector pin 53 (+) and pin 34 (-) Ignition "ON"
Display: 5 V
Connect voltmeter to control module connector pin 44 (+) and pin 34 (-)
Ignition "ON"
Display: in idle position approx. 0.55 V
with wide open throttle approx. 4.5 V
Measure resistance
Ignition "OFF"
Pull control module connector off the adapter, as otherwise the measurement result will be falsified.
Connect ohmmeter to pin 44 and pin 34
Display: Idle position
Wide open throttle
Test point 18
Vehicle speed
DTC 120
Test signal with an oscilloscope.
To do this, connect oscilloscope with terminal 79.
Ignition "ON"
Rotate right rear wheel by hand.
This must produce a square-wave signal of variable frequency.
NOTE: After remedying the fault, erase the ABS/TC fault memory.
Test point 19
Load detection
DTC 121
Possible fault causes:
- Incorrect cruise control adjustment
- Throttle potentiometer defective
- Engine drawing in secondary air
Test point 20
Engine temperature sensor (double NTC thermistor, coolant temperature)
DTC 123
Measure resistance:
Pull control module connector off the adapter, as otherwise the measurement result will be falsified.
Connect ohmmeter to pin 74 and pin 34.
Display: approx. 2395 Ohms at 25 °C
at 90 °C: 242.5 ± 13.2 Ohms
Test point 21
Intake air temperature
DTC 124
NOTE: The intake air temperature sensor is integrated in the hot film mass air flow sensor.
Measure resistance:
Pull control module connector off the adapter, as otherwise the measurement result will be falsified.
Connect ohmmeter to pin 15 and pin 45.
Display: 1.5 - 3.5 kOhms at 15 - 30°
Test point 22
Oil temperature
DTC 125
Measure resistance
Pull control module connector off the adapter, as otherwise the measurement result will be falsified.
Connect ohmmeter to adapter terminal 34 and terminal 73 Display: 15.4 kOhms at an ambient temperature of approx. 25 °C
Measure voltage
Push control module connector onto the control module. Pull connector off the oil temperature sender. Connect voltmeter to pin 1 and pin 2 Display: approx. 5 V
Test point 23
Injector valve, cylinder 123456
DTC 150 - 155
Check voltage supply
Pull off valve connector
Connect voltmeter to connector pin 1 and ground (engine)
Display: Battery positive voltage
Measure coil resistance
Connect ohmmeter to the contacts of the injection valve
Test value: 12 ± 0.3 Ohms
Injection driver
Adjust oscilloscope according to the manufacturer s instructions. Connect auxiliary cable (1 684 463 093) from Messrs. Bosch between the injection valve and connector. Connect oscilloscope with the auxiliary cable according to the manufacturer s instructions.
IMPORTANT: The Tester cables must not come into contact with ground.
Start engine. The following signal must be visible if the injection driver is functioning properly and the Tester connections are correct:
Test point 24
Check Engine MIL
DTC 165
Check wire from DME control module connector terminal 8 to instrument cluster terminal III/2 for short to ground, short to B+ and open circuit.
Test point 25
Fuel pump relay driver
DTC 167
1. Measure voltage
Connect voltmeter to fuel pump relay terminal 30
Display: 12 V
If there is no display, check fuse in row C, No. 4.
2. Connect voltmeter to fuel pump relay terminal 86
Display: 12 V
If there is no display, check DME relay.
3. Check wire between fuel pump relay pin 85 and DME control module connector pin 63 for continuity and short circuit.
Test point 26
IACV break winding
IACV make winding
DTC 168, 169
1. Connect voltmeter to control module connector terminal 54 (+) and terminal 6 (-)
Ignition "ON"
Display: 12 V
2. Measure resistance of windings
Pull off control module connector
Connect ohmmeter to break winding terminal 29 and terminal 54
Display: 15.8 Ohms
Connect ohmmeter to make winding terminal 2 and terminal 54
Display: 18.4 Ohms
Test point 27
A/C compressor control
DTC 170
Connect voltmeter to A/C compressor relay terminal 86 and ground (activated via DME relay)
Ignition "ON"
Display: 12 V
Connect voltmeter to relay terminal 30 and ground
Ignition "ON"
If voltage not present:
Check heater relay No. 18 (in the driver's footwell).
Check wire from relay terminal 85 to DME control module connector pin 62 for continuity.
Check A/C request
Connect voltmeter to control module connector pin 69 and ground
Ignition "ON"
Switch on A/C request
Display approx. 10 V
Test point 28
Camshaft adjustment, bank 1 and bank 2
DTC 174, 178
Measure voltage
Bank 1, cylinders 1 - 3
Connect voltmeter to control module connector or adapter pin 52 and pin 54
Ignition "ON"
Display: Battery positive voltage
Measure voltage
Bank 2, cylinders 4 - 6
Connect voltmeter to control module connector or adapter pin 25 and pin 54
Ignition "ON"
Display: Battery positive voltage
Pull off valve connector and measure voltage between pin 1 (+) and ground (engine)
Ignition "ON"
Display: approx. 12 V
NOTE: Power is supplied via the DME relay
Test point 29
Knock sensors 1 and 2
DTC 210, 211, 212, 213
1. Check fastening of the knock sensors (torque and type of hexagon head bolts)
2. Check wiring harness and plug connections according to the wiring diagram
Allocation:
Knock sensor 1, pin 13 on the control module connector
Knock sensor 2, pin 41 on the control module connector
Ground of knock sensors, pin 71 on the control module connector
3. Loosening and re-tightening the knock sensors may eliminate any excess contact resistance.
Test point 30
CAN timeout
DTC 236
Read out the fault memory of the Tiptronic and remedy the fault if present.
Check wiring for continuity, short to B+ and short to ground.
1. DME control module connector pin 85 to Tiptronic control module connector pin 85.
Ignition "OFF"
2. DME control module connector pin 86 to Tiptronic control module connector pin 86.
Ignition "OFF"
Measure resistance
Pull the control module connector off the adapter before measurement, as otherwise the measurement result will be falsified.
Connect ohmmeter to pin 85 and pin 86
Display: approx. 121 Ohms
Test point 31
Driver, engine compartment purge fan
DTC 251
1. Connect voltmeter to fan relay (connection point 8 in the rear) terminal 30 and ground.
Display: approx. 12 V
If nothing is displayed, check fuse B 4.
2. Connect voltmeter to fan relay terminal 86 and ground.
Display: approx. 12 V
If nothing is displayed, check the DME relay.
3. Check the fan relay
On the relay base, jumper terminal 30 and terminal 87 with a test cable.
Fan starts: Relay defective
Test point 32
Driver, fans
DTC 253
1. Perform drive link diagnosis with the System Tester.
2. Check fuse C 8 for fan 2 and fuse C 10 for fan 1.
3. Connect voltmeter to terminal 30 of the individual relays and ground.
Display: approx. 12 V
4. Connect voltmeter to terminal 86 of the individual relays and ground.
Ignition "ON"
Display: approx. 12 V
5. Fan function test:
On the relay base, jumper terminal 30 and terminal 87 with a test cable.
The fan must start, otherwise the fan or lead is defective.
Test point 33
Signal from airbag
DTC 301
In the event of an accident, the DME control module receives the signal "fuel pump off" from the airbag control module.
Test the airbag signal with an oscilloscope. To do this, connect the oscilloscope with pin 12 of the control module connector and ground.
The following signal must be visible.
Test point 34
PWM interface, actual engine torque
DTC 302
Check actual engine torque
1. Connect oscilloscope. Connect the Tester cable with DME control module connector or adapter terminal 58 and ground. The following signal must be visible with ignition "ON".
2. Start engine. The following signal must be visible.
3. If signal is not visible, check wire between DME control module connector pin 58 and ABS control module connector pin 27 for continuity and short circuit.
Check actual engine torque
1. Connect oscilloscope. Connect Tester with DME control module connector or adapter pin 48 and ground. The following signal must be visible with ignition "ON".
2. Start engine. The following signal must be visible.
3. If signal is not visible, check wire between DME control module connector pin 48 and ABS control module connector pin 13 for continuity and short circuit.
Test point 35
Timing chain out of position, bank 1 and bank 2
DTC 322, 325
Possible fault cause:
Allocation of exhaust camshaft and inlet camshaft does not agree.