Climate control codes
From Knowledgebase
This page describes how to read the Automatic Climate Control (ACC) diagnostic trouble codes that the climate control system in both the early and late versions of the digital climate control system.
Contents |
Early Version
Starting in 1986 the type 44 cars used a General Motors digital climate control system. This earlier version of the system that Audi continued development on could display fault codes, and also 23 channels of useful information readouts.
If the LED next to your "Outside Temperature" button is flashing this indicates your system has a stored fault code. This does NOT keep its memory when you shut off the ignition.
Accessing the early version diagnostic readout
Simply press and hold the "Outisde Temperature" button and simultaneously press the "Off" button. The display will now read "'01", viola you are in. To scroll through the 23 channels of data simply push the "Warmer" (red) button until you reach the channel you desire. To enter that channel press the blue "Cooler" button. The use of each channel is described below.
Early version fault channels
- '01 : System Faults. Use this channel to display fault codes, which are described in the next section.
- '02 : Not Used
- '03 : Interior temp sensor reading. This is not in an actual temp reading, there is a chart needed to convert this reading.
- '04 : Outside temp sensor in A/C intake. Again a chart is needed to convert this reading.
- '05 : Outside temp sensor in front of radiator. As usual, you need the chart.
- '06 : Not Used
- '07 : Graphic display of control head output. Again a graphic is needed to understand the readout.
- '08 : Specified position of temperature regulator flaps.
- '09 : Actual position of temperature regulator flaps. Hint: Compare this value to the value of channel '08 - if they are vastly different you have a problem with the control of the flap.
- '10 : Specified blower voltage.
- '11 : Vehicle voltage. Use this for any time you need to know your system voltage - great for charging system tests.
- '12 : Not Used
- '13 : Ambient temperature switch. This disables the compressor if outside temp is below about 38 degrees F.
- '14 : Not Used.
- '15 : Kickdown switch input on auto trans cars. Used to disable A/C when the throttle is opened enough to activate the kickdown switch.
- '16 : Engine coolant overheat switch input. This disables the A/C if the multi-function temp sensor reports that the engine is overheating.
- '17 : Not used
- '18 : Not used
- '19 : Not used
- '20 : Not used
- '21 : A/C on signal
- '22 : Number of times system voltage dropped under 10.5 volts.
- '23 : Not used
Channel 01 fault codes
Comming soon.
Later Version
The early 90s ACC includes a 61-channel OBD (On Board Diagnostic) display that can be accessed without the use of special tools. It can used to diagnose problems with the ACC system. Owners of cars without ACC will need a VAG 1551 Scan Tool to read error codes.
Accessing the late version ACC OBD readout
You must first set the ACC into diagnostic mode. Then you can cycle through the different channels and call up the desired information.
1. Set the ACC into diagnostic mode
- Turn the car ignition On.
- Press and hold the Recirculation button.
- Press and hold the Up Arrow button.
- Release both buttons.
The ACC display should show "01c", which indicates channel 1.
2. Select a channel
- Press the temperature + or temperature - buttons
3. Call up the desired information
- Select desired channel
- Press the Recirculation button
4. Exit the diagnostics
- To leave the diagnostics mode, press the AUTO button,
- or switch the ignition off.
The Diagnostic Channels
There are 61 diagnostic channels. They display as 01c, 02c, etc.
1 System malfunction - displayed as a Diagnostic Trouble Code (DTC)
2 Digital value of Interior Temperature Sensor, in Headliner
3 Digital value of Interior Temperature Sensor, in Instrument Panel
4 Digital value of Fresh Air Intake Duct Temperature Sensor
5 Digital value of Outside Air (Ambient) Temperature Sensor, front
6 Digital value of Outside Air (Ambient) Temperature Sensor
7 Digital value of Ambient Temperature Sensor at Fresh Air Blower
8 Digital value of Temperature Regulator Flap Motor Potentiometer
9 Delta value of Temperature Regulator Flap
10 Non-corrected specified value of Temperature Regulator Flap
11 Digital value of Central Flap Motor Potentiometer
12 Specified value of Central Flap
13 Digital value of Footwell/Defroster Flap Motor Potentiometer
14 Specified value of Footwell/Defroster Flap
15 Digital value of Air Flow Flap Motor Potentiometer (Disregard for US/Canada models)
16 Specified value of Air Flow Flap
17 Vehicle Speed (km/h)
18 Actual Fresh Air Blower voltage (Volts)
19 Specified Fresh Air Blower voltage (Volts)
20 A/C Compressor (A/C Clutch) voltage (Volts)
21 Number of low voltage occurrences, non-transient
22 Cycle condition of A/C Refrigerant High Pressure Switch
23 Cyclings of the A/C Refrigerant High Pressure Switch
24 Cyclings of the switches, absolute non-fluctuating
25 Analog/Digital value, Kick-Down Switch
26 Analog/Digital value, Engine Coolant Temperature (ECT) Warning Light
27 Coding value
28 Engine Speed (RPM)
29 A/C Compressor speed in rpm (Equals Engine Speed x 1.28)
30 Software version
31 Display check (all segments of A/C Control Head display light up)
32 Potentiometer malfunction counter, Temperature Regulator Flap
33 Potentiometer malfunction counter, Central Flap
34 Potentiometer malfunction counter, Footwell/Defroster Flap
35 Potentiometer malfunction counter, Air Flow Flap
36 Feedback value, cold end-stop, Temperature Regulator Flap Motor Potentiometer
37 Feedback value, hot end-stop, Temperature Regulator Flap Motor Potentiometer
38 Feedback value, cold end-stop, Central Flap Motor Potentiometer
39 Feedback value, hot end-stop, Central Flap Motor Potentiometer
40 Feedback value, cold end-stop, Footwell/Defroster Flap Motor Potentiometer
41 Feedback value, hot end-stop, Footwell/Defroster Flap Motor Potentiometer
42 Feedback value, cold end-stop, Air Flow Flap Motor Potentiometer
43 Feedback value, hot end-stop, Air Flow Flap Motor Potentiometer
44 Vehicle operation cycle counter
45 Calculated Interior temperature (internal software, in digits)
46 Outside (ambient) temperature, filtered, for regulation (internal software)
47 Outside (ambient) temperature, unfiltered, (internal software, in Celsius)
48 Outside (ambient) temperature, unfiltered (in digits)
49 Malfunction counter for speedometer (vehicle speed) signal
50 Standing time (in minutes)
51 Engine Coolant Temperature (ECT), in Celsius
52 Graphics channel 1, see chart below. NOTE: When Diagnostic Channel 52 is selected, .--.-. is displayed first. A/C compressor switch-off conditions are identified by illuminated segments of the .88.8. display.
53 Graphics channel 2, see chart below. NOTE: When Diagnostic Channel 53 is selected, .--.-. is displayed first. A/C system electrical outputs are identified by illuminated segments of the .88.8. display.
54 Control characteristics
55 Outside (ambient) temperature, in Celsius or Fahrenheit depending on the setting of the A/C control head
56 Temperature in Celsius, from Interior Temperature Sensor, in Headliner
57 Temperature in Celsius, from Interior Temperature Sensor, in Instrument Panel
58 Temperature in Celsius, from Fresh Air Intake Duct Temperature Sensor
59 Temperature in Celsius, from Outside Air (Ambient) Temperature Sensor
60 Temperature in Celsius, from Ambient Temperature Sensor at Fresh Air Blower
61 Software version (latest)
The Diagnostic Trouble Codes
| Code | Explanation |
|---|---|
| 0.00 | No Malfunction Present |
| 02.1 | (G86) Interior Temperature Sensor, in Headliner, static open. The default value of 128 appears if sensor fails. |
| 02.2 | Interior Temperature Sensor, in Headliner, static short; See 02.1. |
| 02.3 | Interior Temperature Sensor, in Headliner, sporadic open |
| 02.4 | Interior Temperature Sensor, in Headliner, sporadic short |
| 03.1 | (G56) Interior Temperature Sensor, in Instrument Panel, static open; see 02.1. |
| 03.2 | Interior Temperature Sensor, in Instrument Panel, static short; See 02.1. |
| 03.3 | Interior Temperature Sensor, in Instrument Panel, sporadic open |
| 03.4 | Interior Temperature Sensor, in Instrument Panel, sporadic short |
| 04.1 | (G89) Fresh Air Intake Duct Temperature Sensor, static open. The value supplied by Temperature Sensor (04.2) is used if sensor fails. |
| 04.2 | Fresh Air Intake Duct Temperature Sensor, static short. See 04.1. |
| 04.3 | Fresh Air Intake Duct Temperature Sensor, sporadic open |
| 04.4 | Fresh Air Intake Duct Temperature Sensor, sporadic short |
| 05.1 | (G17) Outside Air (Ambient) Temperature Sensor, front, static open. The value supplied by Temperature Sensor (05.2) is used if sensor fails. |
| 05.2 | Outside Air (Ambient) Temperature Sensor, front, static short, see 05.1. The default value of 128 is programmed if sensors G89 and G17 (05.1) both fail. |
| 05.3 | Outside Air (Ambient) Temperature Sensor, front, sporadic open |
| 05.4 | Outside Air (Ambient) Temperature Sensor, front, sporadic short |
| 06.1 | (G110) Engine Coolant Temperature (ECT), A/C static open. Engine Coolant Temperature is calculated if sensor should fail or is not installed; diagnosis occurs only above 0?C (32?F). |
| 06.2 | Engine Coolant Temperature (ECT), A/C static short, see 06.1 |
| 06.3 | Engine Coolant Temperature (ECT), A/C sporadic open |
| 06.4 | Engine Coolant Temperature (ECT), A/C sporadic short |
| 07.1 | (G109) Ambient Temperature Sensor at Fresh Air Blower, static open. Programmed corrective value = 0. |
| 07.2 | Ambient Temperature Sensor at Fresh Air Blower, static short, see 07.1 |
| 07.3 | Ambient Temperature Sensorat Fresh Air Blower, sporadic open |
| 07.4 | Ambient Temperature Sensor at Fresh Air Blower, sporadic short |
| 08.1 | (G92) Temperature Regulator Flap Motor Potentiometer, static open. Temperature Regulator Flap Motor will no longer be controlled automatically; manual adjustment only. |
| 08.2 | Temperature Regulator Flap Motor Potentiometer, static short, see 08.1 |
| 08.3 | Temperature Regulator Flap Motor Potentiometer, sporadic open |
| 08.4 | Temperature Regulator Flap Motor Potentiometer, sporadic short |
| 08.5 | Temperature Regulator Flap, static block. Motor is cycled, software attempts to eliminate block. |
| 08.6 | Temperature Regulator Flap Motor Potentiometer, malfunction |
| 08.7 | Temperature Regulator Flap, sporadic block |
| 11.1 | (G112) Central Flap Motor Potentiometer, static open. Central Flap Motor will no longer be controlled automatically; manual adjustment only. |
| 11.2 | Central Flap Motor Potentiometer, static short, see 11.1 |
| 11.3 | Central Flap Motor Potentiomenter, sporadic open |
| 11.4 | Central Flap Motor Potentiometer, sporadic short |
| 11.5 | Central Flap, static block. Motor is cycled; software attempts to eliminate block. |
| 11.6 | Central Flap Motor Potentiometer, malfunction |
| 11.7 | Central Flap, sporadic block |
| 13.1 | (G114) Footwell/Defroster Flap Motor Potentiometer, static open. Footwell/Defroster Flap Motor will no longer be controlled automatically; manual adjustment only. |
| 13.2 | Footwell/Defroster Flap Motor Potentiometer, static short, see 13.1 |
| 13.3 | Footwell/Defroster Flap Motor Potentiometer, sporadic open |
| 13.4 | Footwell/Defroster Flap Motor Potentiometer, sporadic short |
| 13.5 | Footwell/Defroster Flap, static block. Motor is cycled; software attempts to eliminate block. |
| 13.6 | Footwell/Defroster Flap Motor Potentiometer, malfunction |
| 13.7 | Footwell/Defroster Flap, sporadic block |
| 15.1 | (G113) Air Flow Flap Motor Potentiometer, static open. Digital value is internally programmed for limp-home mode. |
| 15.2 | Air Flow Flap Motor Potentiometer, static short, see 15.1 |
| 15.3 | Air Flow Flap Motor Potentiometer, sporadic open |
| 15.4 | Air Flow Flap Motor Potentiometer, sporadic short |
| 15.5 | Air Flow Flap, static block. Motor is cycled; software attempts to eliminate block. |
| 15.6 | Air Flow Flap Motor Potentiometer, malfunction |
| 15.7 | Air Flow Flap, sporadic block |
| 17.0 | Vehicle Speed Signal faulty |
| 18.1 | Fresh Air Blower voltage, static |
| 18.3 | Fresh Air Blower voltage, sporadic |
| 20.1 | A/C compressor voltage not OK - static. Compressor remains off until voltage is greater than 10.8V for at least 25 seconds. |
| 20.3 | A/C compressor voltage not OK - sporadic |
| 22.1 | (F118) A/C Refrigerant High Pressure Switch, static open. Compressor remains off until switch closes. |
| 22.3 | A/C Refrigerant High Pressure Switch, sporadic open |
| 22.5 | A/C Refrigerant High Pressure Switch, 120X open. Compressor re-engagement circuit, VAG 1551 Scan Tool function. |
| 29.1 | Belt slip detection "soft," static |
| 29.2 | Belt slip detection "hard," static |
| 29.3 | Belt slip detection "soft," sporadic |
| 29.4 | Belt slip detection "hard," sporadic |
| 52.1 | High pressure occurrences more than 30 times |
| 52.2 | Ambient temperature sensor at fresh air blower less than 27d (3dC) |
| 52.3 | ECON mode selected |
| 52.4 | Off selected |
| 52.5 | Ambient temperature too low |
| 52.6 | Engine Management System (compressor will remain off for 3-12 seconds) |
| 52.7 | Segments 7, 14, and 21 must illuminate simultaneously to indicate system function is OK |
| 52.8 | A/C refrigerant high pressure cut-out switch |
| 52.9 | A/C manually switch off (A/C Standby cancelled) |
| 52.10 | Low voltage |
| 52.11 | Kickdown switch (via transmission control module, compressor off for 12 seconds maximum) |
| 52.12 | Engine coolant temperature warning light switch |
| 52.13 | A/C Refrigerant low pressure switch |
| 52.14 | Segments 7, 14, and 21 must illuminate simultaneously to indicate system function is OK |
| 52.15 | not used |
| 52.16 | Slippage or blockage |
| 52.17 | Engine speed less than 200-500 RPM |
| 52.18 | not used |
| 52.19 | Engine speed greater than 6000 RPM |
| 52.20 | not used |
| 52.21 | Segments 7, 14, and 21 must illuminate simultaneously to indicate system function is OK |
| 52.22 | Visible with A/C compressor on; not visible with A/C compressor off |
| 53.1 | Temperature flap in cold air position |
| 53.2 | Temperature flap in warm air position |
| 53.3 | not used |
| 53.4 | Central flap in instrument panel outlet position |
| 53.5 | Central flap in footwell/defrost outlet position |
| 53.6 | not used |
| 53.7 | Segments 7, 14, and 21 must illuminate simultaneously to indicate system function is OK |
| 53.8 | Footwell/Defroster flap in defrost position |
| 53.9 | not used |
| 53.10 | Airflow flap open |
| 53.11 | Airflow flap closed |
| 53.12 | not used |
| 53.13 | Footwell/defroster flap in footwell position |
| 53.14 | Segments 7, 14, and 21 must illuminate simultaneously to indicate system function is OK |
| 53.15 | First speed of coolant fan on |
| 53.16 | Fan for in-car temperature sensor |
| 53.17 | Fresh air/recirculation flap closed |
| 53.18 | Heater valve closed |
| 53.19 | Bi-directional wiring harness |
| 53.20 | A/C compressor on |
| 53.21 | Segments 7, 14, and 21 must illuminate simultaneously to indicate system function is OK |
| 53.22 | not used |
KentMcLean - 06 Feb 2005 Cody 23:10, 18 December 2007 (PST)
