I got some '02 XC side markers for my 98 S70T5. A little modification and they pop in. On the left side, it looked like it was 'pre-wired', an un-connected set of wires in the wheel well(hey this will be easy, yeah right!. But the wires ran past the turn signal and in the engine compartment somewhere. So, keeping them intact,letting them still run into the engine bay, I 'patched' the two wires to the turn signal. Side marker goes on and off with blinker, but a loud tick tock of the blinker was coming from somewhere under the car!! It was like someone had a speaker under the car with the blinker noise! What did I tap into??? So not wanting a loud tick-tock, I cut the wires so it just goes to the side markers and thats it. Where did they go and what do they do? As described before, it wasn't connected to anything in the wheel well.

NO wires of this type on the right side, thats weird!

Get in the car start it up, LAMBDA light. Coincidence?? Please help!

-Ananda

What colors were the wires you "tapped into"?
Did the connector have just two pins, or 3 or 4?
Volvo uses two different engine management systems, with different sensors, but a common harness. For example, turbocharged models have a boost pressure sensor, and some models have two oxygen sensors, others just one.

Thanks for the response!!

The wires were white/blue and Red/blue. It was a two prong harness, 'molded' for what to me looked like a stock side marker. I don't get why these wires would be 'hanging' unconnected to anything behind the wheel well, unless it was for the lights.

This is indeed baffling.

I studied all of the 1998 S70 wiring diagrams in search of a 2 pin connector with blue/white and blue/red wires. If you did have prewired connectors in place for the "euro" side marker/directional lamps, the colors would be green and black.

One possibility is a pair of wires that run from the Engine control unit to a solenoid valve used to purge the evaporated gas fume storage canister. Those are the correct colors and a malfunction might trigger the "lambda" lamp. The noise you heard may have been that valve operating in syncronization with the flasher. However, I may be missing some details of your wiring arrangement, as I do not understand how connecting to those two wires could flash a bulb.

First off, thanks for your time and your sharing of your knowledge!!

For some reason at the time, I had thought that the white/blue, blue/red wires may somehow need to go into the engine bay. So i did not cut them, i just peeled the cover off. Then i tapped them into the green and black wires that go to the front turn signal. At that point, the front turn signal was giving power to the side marker AND to whatever was on the other end of the wires, I guess the valve. But the end that I hooked up to the side markers wasn't hooked up to anything, it was attached to the inside of the wheel well. Does the diagram show where the blue/white, blue/red harness should be connected to. Was it not purging since it wasn't connected? AND do i need to see the dealer, to either fix the valve, and/or turn the Lambda off?!

Thanks again!!

Your description claries things somewhat. I can now understand how the flasher and unknown sound could occur in synchronization.

According to the Volvo drawings, the purge valve is located in the rear, near the fuel tank, so it is possible that the sound (of the valve operating) could appear to come from below and to the rear. It is operated by the engine comtrol computer, which is located in the engine bay. The Volvo drawing does not show a connector in the purge valve wires, but it is possible on was added for diagnostic purposes. While I cannot be 100% sure that the wires you described connect to that valve, it is the only component I can find that matches both the number of wires (2) and wire colors (Bl/R and Bl/W).

It is possible that the ECU detected, and has stored, a suspected component fault. It may clear itself after 50 (or so) operations of the ignition without a repeat of the fault condition. Otherwise, you may need access to a "scan tool" to clear (turn off) the lamp. I assume the car seems to be running OK. You might also check of your fuses visually; your temporary connection may have caused one to blow.

Yeah, the car is running fine, and I did check all of the fuses. It was just the noise and then then Lambda light that worried me. So... I have some other warranty work being done at the dealer later this month, if the lights not off by then I guess I'll have to tell thim about my bonehead move and/or I'll have them do a diagnostic and reset it.

Thanks again for your expertise.

-Ananda