1999 AUDI A4 engine

01-69

DTC
Description of malfunction
Corrective action
SAE
VAG


P1620 18028 Engine coolant temperature signal
Open/short to B+
P1621 18029 Engine coolant temperature signal
Short to ground - Check coolant temperature signal Page 24
-181
P1622 18030 Engine coolant temperature signal
Range/Performance Note for malfunctions P1620, P1621 and P1622:
The Engine Control Module (ECM) receives the "Coolant temperature signal" from the instrument cluster. When the ECM
receives this signal the boost pressure will be decreased.
Pa
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01-70

DTC
Description of malfunction
Corrective action
SAE
VAG


P1624 18032 MIL Request Sign. active Exhaust relevant malfunction from Transmission Control Module (TCM),
MIL is switched on by TCM
Repair Manual, Automatic Transmission, Repair Group 01, Perform
On Board Diagnostic - Check DTC Memory of TCM
P1626 18034
Data-Bus Powertrain
2)
Missing message from fuel
injection pump - Check CAN-Bus Page 24
-201
2) With this malfunction the exhaust Malfunction Indicator Light (MIL) is only switched on by the ECM, if the malfunction is
recognized after the engine has been restarted. Significance of MIL Page 01
-3 .
Note for malfunction P1624:

MIL stands for Malfunction Indicator Light. Once the Engine Control Module (ECM) recognizes a malfunction that
decreases the exhaust emissions it switches the MIL on.
The MIL is switched on only by the Engine Control Module (ECM), since the ECM has the only connection to the MIL..
Malfunction that decrease the exhaust emissions can also be recognized by the Transmission Control Module (TCM),
These malfunction are also indicated by the MIL.
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Once the TCM recognizes a malfunction that decreases the exhaust emissions it sends a message to the ECM, the ECM
then switches the MIL on. Parallel to this is the malfunction P1624 stored in the ECM noting that the MIL is switched on
due to a transmission problem and not because of a engine problem.
Pa
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01-72

DTC
Description of malfunction
Corrective action
SAE
VAG


P1639 18047 Accelera. Pedal Pos.
Sensor1+2
Range/Performance
1) 3)
- Check acceleration pedal position sensor Page 24
-159
P1640 18048 Internal Control Module
(EEPROM)
Error
2) - Replace Engine Control Module (ECM) Page 24
-24
.
P1648 18056 Data Bus Powertrain
Malfunction - Check data exchange between Engine-/ABS-/Transmission control
module Page 24
-201

P1649 18057 Data Bus Powertrain
Missing message from ABS
Control Module Repair Manual, Brake System On Board Diagnostic (OBD), Repair
Group 01, checking DTC memory of ABS control module
- Check DTC memory of ABS control module
- Check data exchange between Engine-/ABS-/Transmission control
module Page 24
-201

1) With this malfunction the EPC (Electronic Power Control) Malfunction Indicator Light (MIL) in the instrument cluster is
switched on by the ECM. Significance of EPC malfunction indicator light Page 24
-142
.
2) With this malfunction the exhaust Malfunction Indicator Light (MIL) is only switched on by the ECM, if the malfunction is
recognized after the engine has been restarted. Significance of MIL Page 01
-3 .
Pa
ge 87 of 166 Motronic s
ystem, On Board Dia
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)
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01-73

DTC
Description of malfunction
Corrective action
SAE
VAG


P1650 18058 Powertrain CAN-bus
Missing message from instrument
cluster - Check data transfer Page 24-201
P1654 18062 Check DTC memory of the instrument
cluster - Check DTC memory of instrument cluster and repair
malfunctions
P1676 18084 Drive by Wire-MIL Circ.
Electrical Malfunction
1) - Significance of Electronic Power Control (EPC) warning light
Page 24
-142

P1677 18085 Drive by Wire-MIL Circ.
Short to B+
1)

P1690 18098 Malfunction Indication Light
Malfunction 2) - Check wiring for exhaust Malfunction Indicator Light (MIL)
Page 01
-4
P1693 18101 Malfunction Indication Light
Short circuit to B+
2)
1) With this malfunction the EPC (Electronic Power Control) Malfunction Indicator Light (MIL) in the instrument cluster is
switched on by the ECM. Significance of EPC malfunction indicator light Page 24
-142
.
2) With this malfunction the exhaust Malfunction Indicator Light (MIL) is only switched on by the ECM, if the malfunction is
recognized after the engine has been restarted. Significance of MIL Page 01
-3 .
Pa
ge 89 of 166 Motronic s
ystem, On Board Dia
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01-74

DTC
Description of malfunction
Corrective action
SAE
VAG


P1851 18259 Data Bus Powertrain
Missing Message from Brake Contr
Repair Manual, Brake System On Board Diagnostic (OBD), Repair
Group 01, checking DTC memory of ABS control module
- Check DTC memory of ABS control module
- Check data exchange between Engine-/ABS-
/Transmission control
module Page 24
-201

P1853 18261 Data Bus Powertrain
Unplausible Message from Brake
Contr.
P1854 18262 Data Bus Powertrain
Hardware Defective
P3262 19718 Exhaust bank 1/2 oxygen sensors
behind catalytic converter
mixed up - Check harness connectors for oxygen sensors and check installed
position of oxygen sensors behind catalytic converter. 1) With this malfunction the EPC (Electronic Power Control) Malfunction Indicator Light (MIL) in the instrument cluster is
switched on by the ECM. Significance of EPC malfunction indicator light Page 24
-142
.
2) With this malfunction the exhaust Malfunction Indicator Light (MIL) is only switched on by the ECM, if the malfunction is
recognized after the engine has been restarted. Significance of MIL Page 01
-3 .
Pa
ge 91 of 166 Motronic s
ystem, On Board Dia
gnostic
(OBD
)
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01-75

Output Diagnostic Test Mode (DTM)


Notes:

The DTM can only be performed with the
ignition switched on and the engine not running.
The DTM is terminated if the engine is started
or if an engine speed pulse is detected.
During the DTM, individual control elements will
be activated for approx. 1 minute, or until the
test program is advanced to the next control
element by pressing the button.

The control elements can be tested either by
listening or by touching.
If the DTM is to be repeated, the engine must
be started. The engine control module needs to
detect an engine speed of more than 300 rpm.
The electric fuel pump runs continuously
throughout the DTM.
Pa
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ystem, On Board Dia
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01-77

Test requirements

Fuses for engine electronics OK
Fuel pump relay OK

- Connect vehicle diagnostic, testing and
information system VAS 5051 or VAG1551 scan
tool and select engine electronics control
module by entering address word "01" Page 01
-9 . When doing this the ignition must be
switched on.
Rapid data transfer
HELP
Select function XX

Indicated on display
- Press buttons -0- and -3- to select function "Output Diagnostic Test
Mode."
Rapid data transfer
Q
03 - Output Dia
gnostic Test Mode

Indicated on display
Pa
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)
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