Reading Actual Values With HHT
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2001 Mercedes-Benz ML55, 2001 Mercedes-Benz ML430, 2001 Mercedes-Benz ML320, 2000 Mercedes-Benz ML55, and 2000 Mercedes-Benz ML430. However, it is still accessible from the selected car via links, so may be relevant.
Connect Hand-Held Tester (HHT) to DLC and follow displayed procedures. Actual values displayed on HHT show normal operation value of A/C systems or components. See ACTUAL VALUES
table. If value is not as specified, check system or components in order. Repair as necessary.
ACTUAL VALUES
| Step |
Test Condition |
Value |
System/Component |
| 01 |
..... |
11-14 Volts |
Voltage Supply Wiring (Circuit No. 30) & Battery |
| 02 |
Engine Operating At Normal Temperature |
About 176°F (80°C) |
Wiring, ECT Sensor & AAM |
| 03 |
Ignition ON |
Ambient Air Temperature About 68°F (20°C) |
Wiring, Outside Temperature Sensor & AAM |
| 04 |
Ignition ON, Blower At Stage 4 |
ON/OFF |
Wiring, Blower Motor Relay, Blower Motor & AAM |
| 05 |
Ignition ON |
ON/OFF |
Wiring, Engine Cooling Fan Stage 1, Aux. Fan & AAM |
| 08 |
Ignition ON |
ON/OFF |
Wiring, Coolant Circulation Pump Relay, Coolant Circulation Pump & AAM |
| 09 |
Engine On, A/C Indicator On, Blower Motor At Stage 4 |
Refrigerant Pressure At 174 psi (12 bar) |
Refrigerant Pressure Sensor |
| 10 |
Engine On, A/C Indicator On, Blower Motor At Stage 4 |
ON/OFF |
AAM, A/C Compressor |
| 11 |
Ignition ON, Activate A/C System |
YES/NO |
Wiring, A/C Push Button Control Module, AAM |