The Mercedes Benz 420SEL is equipped with the ASR (Acceleration Skid Regulation) system, which helps to prevent wheel slip during acceleration. When the ASR system detects wheel slip, it reduces engine power and/or applies the brakes to the affected wheel(s).
If the ASR system is malfunctioning, you may see an ASR code displayed on the instrument panel. The code will be a four-digit number, and each digit represents a different component of the ASR system.
Here is a table of ASR codes and their meanings:
```
Code Component
01 ASR control unit
02 Wheel speed sensor
03 Hydraulic unit
04 ASR relay
05 ASR switch
06 ASR warning lamp
07 ASR solenoid valve
08 ASR pressure sensor
09 ASR differential lock switch
```
To diagnose an ASR code, you will need the following tools:
- Scan tool or code reader
- Multimeter
- Socket set
Instructions:
1. Connect the scan tool or code reader to the diagnostic port under the hood of the 420SEL.
2. Select the "ASR" menu on the scan tool or code reader.
3. Read the ASR code that is displayed.
4. Refer to the table above to identify the component that is associated with the code.
5. Disconnect the scan tool or code reader.
6. Use the multimeter to test the component that is associated with the code. The specific tests that you will need to perform will vary depending on the component.
7. If the component is found to be faulty, replace it.
8. Clear the ASR code using the scan tool or code reader.
Common ASR Codes for the 1991 Mercedes Benz 420SEL
The following are some of the most common ASR codes that you may encounter on the 1991 Mercedes Benz 420SEL:
- 01: ASR control unit
- 02: Wheel speed sensor
- 03: Hydraulic unit
- 04: ASR relay
- 06: ASR warning lamp
- 08: ASR pressure sensor
If you see one of these codes on your 420SEL, it is important to diagnose and repair the problem as soon as possible to avoid potential safety risks.
