01 S60 intermittent hard start

[cn90]

Intermnittent hard start in a P2 car, always look into PEM.
Just get a good used PEM as diagnostic tool.

[rbodor3]

No PEM on my '01.

I disassembled and cleaned the ECM chiller box, ensuring no evidence of water intrusion or air infiltration. Confirmed that cab air comes in the box from the back. Confirmed no corrosion on ECM pins, and no evidence of damaged or corroded pins. The original insulation on the chiller pipe (from cab) wasn't sealing, so during reassembly I temporarily wrapped it in metal HVAC tape to try and keep the insulation from crumbling further. I'm considering what long-term solution I may implement.

The chiller box has been abused from years of getting banged up, but PN is discontinued w/ no supersession. It appears Volvo changed the design for a new fan-powered chiller box (8645259 cover, 9452548 intermediate, 9452547 bottom, and 8651422 adapter in lieu of the fan-powered version). Parts are en-route, nearly all are backordered

Recently I had intermittent "bulb out" for the front low beams and rear taillights (brake & fog were good). Upon further inspection, discovered that wiggling the relays CMI5 (parking) and CMI7 (low beam) caused intermittent function. My CEM is recent from XemodeX, so I inspected the "vehicle-side" portion of the CEM. Relay sockets appeared expanded. Although bending them slightly (w/ pick tool) was successful, the function remained intermittent. I pulled all the relays (30765042) and added a bit of solder to the larger pins. This worked. Because I see that multiple relays simultaneously toggle on/off during my failure, I do NOT think this is the cause of my issue - although it may be one contributing factor.

[rbodor3]

• Removed ECM and cleaned both harness and module -side connectors w/ QD Contact Cleaner. No signs of corrosion, loose pins.

• Disassembled ECM and cleaned PCB.

• Conformal coated PCB w/ 3x light passes of silicone (200*C MG Chemicals 422B-340G spray).

• Laid a bead of RTV (Permatex, grey IIRC) along the edges of ECM housing. A thick bead was needed around the bulkhead connector, due to shape.

• Reassembled ECM, lightly packed dielectric grease into connector during reinstall.

Humidity in Houston has been lower, but I've measured at least (3) days near 80%. Car consistently starts. I'll continue to monitor through March before concluding issue resolved.