PeachParts Mercedes-Benz Forum - View Single Post

stephenson · #4 01-05-2013, 06:13 PM

Was able to trick the ASD solenoid into operation - with car on lift I used floor jack to immobilize one of the rear wheels to prevent turning - jumpered terminals 8 and 10 and put in neutral - got some lockup by spinning one of the wheels - then had someone turn on key to start position without engaging started - no change in lockup and could still spin the wheel. Helper started engine while wheel was being turned and the differential locked up immediately. Basic test to confirm ASD solenoid is working.

Spent afternoon troubleshooting using 35-516 protocols starting on page 669, going through every script except for the ones that required ABS testing routines (some interact with ASD system) - working backwards toward the ASD triangular bulb.

The RF wheel speed sensor is still showing 8.15V at the ASD module block when spinning the wheel once per second (approximately - per the 35-516 testing protocol). It should be approximately 4 VDC. Left wheel sensor reads 4 VDC per spec.

I didn't find any open circuits in wires or connectors - until got back to the ASD triangular light bulb base ... I had tested through the wire connector, the small electronics board on the back of the bulb base, etc ... and, the bulb was bad. Odd since it tested fine 10 days ago when I was checking it first ... the Osram 12/1.2 bulbs are pretty common items so I got 4 (marked Philips 12/1.2 instead of Osram 12/1.2 - different manufacturer but same markings for wattage and base) and replaced the others in the cluster while putting it back together.

Connected everything back up and got the triangular light during start sequence and then it went out when the engine started per normal.

Test drive - the ASD triangular came on several times as I exited corners without spinning wheels - sort of a hyper sensitivity to differential wheel movement, maybe? I checked the fluid level and it was no longer on the dipstick so am ordering some more to see if it was hydraulic fluid starved ... grasping as straws.

At least light is now operating per normal start sequence.

More when I get the oil and/or anything else weird happens.