01 S60 intermittent hard start

[abscate]

Discovered the PTC heater wiring leads have exposed wires & corrosion right at the connector. You can better see this in the photo after I cut the connector off the main harness. I suspect this was causing a short, and shares a common ground w/ the ETM, and common power to the TCV. Since the corrosion was so close to the connector, I decided to repair:
Sprayed w/ QD Contact Cleaner
Dabbed w/ Starbrite liquid electrical tape
Slipped heat shrink over each lead
Re-soldered to the main harness (w/ heat shrink), and new loom

Again, it's running fine. No fault set at any time.

Well done. Its not glamorous telling people to look for wiring faults, I appreciate how diligent it must have been inspecting wires until you found that.

[rbodor3]

I drive my car very rarely - typically takes me 2 months to go through a tank of gas. The failure came back yesterday. I will keep digging into some of the further reaches of the harness, that I haven't yet unloomed & inspected. Will update w/ findings.

[abscate]

Good luck! At least you know to critically look at all wiring, every where.

14) Replaced crank and cam position sensors (swap-nostics)

Swap-nostics gave me a good chuckle. It has its place , but taking time to diagnose saves time and money ultimately.

[rbodor3]

I found about (3) sensors with similar wire damage near the sensor, showing exposed wires. In 1 of these cases, the wire was twisted in a way that might have allowed them to short together intermittently. In all (3) of these, the damage was right at the connector - unable to repair without replacing the pins. Instead, I cleaned the exposed wires and applied liquid electrical tape. It's unclear if this is what's causing the intermittent failure (which hasn't recurred).
I'm going to try and source replacement pins, they appear to be Tyco pins. If anyone has any ideas, LMK. No brand on any of the connectors, unfortunately.

[br0dy519]

Which sensors? Often there's replacement pigtails available that you can splice in.

[rbodor3]

Damn, you're right. I just found it. I looked a few years ago and didn't have any luck, but lo-and-behold:
https://usparts.volvocars.com/a/Volvo_2 ... 75950.html

[leapdragon]

For the experts... I was just coming here to ask a similar question about an '07 XC70.

Every now and then, will crank for 6-8 turns of the crank instead of 1 turn to start. Even more rarely, when it finally starts, it will go into limp mode and set the code for crankshaft position sensor immediately upon starting. When that happens clear codes, start again, and all is well. I replaced the crankshaft position sensor but the problem persists.

Other than this start problem, it runs perfectly, no other issues.

I inspected the wiring near the sensor but I don't see any problems. Thoughts of other places to check?

[br0dy519]

It's possible your starter is aging and causing electromagnetic interference and causing CANBUS communication issues. Mine often came up as a BRAKE FAILURE message. See my thread here: viewtopic.php?t=100183

You can either try and physically route the wiring away from the starter, or replace the starter which is the more permanent solution.

[rbodor3]

@br0dy519: I installed a new Bosch starter (3) months ago, while also shielding the starter wire w/ foil-lined sheathing similar to this. Neither improved the issue. But I'll look into it more - may be entirely reroute the starter cable.

Problem continues intermittently. Since last update I found an original (213k mile) coilpack w/ minor cracks, and replaced w/ new OE. Have continued to look for other wire shorts to no avail.

Everytime the failure occurs the ECM acts as if reset: fuel trims and readiness status reset. Pulling at straws I pulled the ECM. There is no gasket/RTV sealing the PCB of the ECM. I'm not sure if that's normal for ME7, but Denso ones do have some RTV. The plastic box my ECM sits in is also badly cracked. I see no evidence of water ingression, but will replace the box (although parts have been discontinued). I will also spray a conformal coating on the PCB and seal the ECM casing. Truly grasping at straws today.

[deano1]

I know this is an old thread now but this reminded me of my wife's 2001 V70 and we were suddenly having some issues where the car was really running like crap plus would barely idle,, not really drive-able.
VIDA was reporting something about the MAP sensor signal and to borrow your term through a process of "swap-nostics" (love that saying) I was able to determine it was not the MAP sensor itself or wiring.
In the end with everything else being exhausted the problem was corrosion on the ECM pins that were assigned with accepting input for the MAP sensor.
Removing ECM and inspecting & carefully cleaning any pin that looked suspect then re seating the ECM was the answer.
Have Not had an issue since.
At now 20 years old these cars are victims of the corrosion gremlin.
I hope that helps
Cheers