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2021 Mach 1 Differential Overheating on track

1,012
947
In the V6L
Another update - my son just got back from driving the car and got it up to 210 on the street. I got under the car and the pump was not running as far as we could tell (no noise, no vibration when I touched it). We then put a heat gun on the diff cover near the temp sensor and got it to read 275 on the dash. Again, no activity from the pump whatsoever.

I'm not sure if the pump is designed to only run when the car is moving, but it definitely wasn't on when we were testing it.

I also went through all of the pids in Forscan while the car was running, and couldn't find anything for the diff.
Well, it sounds like the pump's really not working. What is working though is the diff temp sensor, and that's good news. Can Forscan find the diff temp PID? If you can't find it, then it's masquerading under a new name. In the back of my mind, I'm wondering if Ford's engineers brought across a control software component originally built for another system, maybe a transfer case or something else in the Ford product line on another vehicle.

If there are no DTC's other than the overheat one (P188A) then the ECU either thinks the pump's working fine or it's not thinking about the pump at all (wrong software). Thing is, just because Forscan can't find a PID doesn't mean it's not there. If a genuine Ford (Bosch) IDS system can't find it, then it's really not there. If you know a shop with a high-end Snap On system or similar, they could probably diagnose it too.
 
Well, it sounds like the pump's really not working. What is working though is the diff temp sensor, and that's good news. Can Forscan find the diff temp PID? If you can't find it, then it's masquerading under a new name. In the back of my mind, I'm wondering if Ford's engineers brought across a control software component originally built for another system, maybe a transfer case or something else in the Ford product line on another vehicle.

If there are no DTC's other than the overheat one (P188A) then the ECU either thinks the pump's working fine or it's not thinking about the pump at all (wrong software). Thing is, just because Forscan can't find a PID doesn't mean it's not there. If a genuine Ford (Bosch) IDS system can't find it, then it's really not there. If you know a shop with a high-end Snap On system or similar, they could probably diagnose it too.

no, I couldn’t find the diff temp pid either. My guess is they moved it into something that Forscan hasn’t decoded yet.

I’m starting to think the car doesn’t know it was there and hasn’t switched it on. While on track, I could watch the temp rise as I went around track, nearly linear. Makes me think it never switched it on.

Going to drop the car off at the dealer today, though they say they are a month behind so it might sit there a while
 
Is there a way you can apply power directly to the pump? Rule out simple mechanical failure.

Unfortunately it’s not as simple as powering the pump. According to the pin-outs that I’ve seen, it’s a six wire connection. 12v power and ground, and four signal wires. The problem is I’m not sure what the signal wires are reading, nor if all of them are required to be powered. Hence, I’m not sure if the basic test I ran is sufficient to get the pump to come on (as in, does it require other conditions to be met in the car - like vehicle speed or trans temp).
 
I've posted this tidbit before and it still rings true...it's likely a little longer now if you add all the new taxes that have cropped up.......................................................https://www.adamsmith.org/blog/miscellaneous/the-tax-poem
 
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Dave_W

Cones - not just for ice cream
418
404
Exp. Type
Autocross
Exp. Level
20+ Years
Connecticut
12v power and ground, and four signal wires.
I found this wiring info. https://www.mustang6g.com/forums/threads/oem-differential-oil-cooler-install.69499/post-1614256
Looks like battery power to pin 2, ground through pin 6, and powering pin 1 acts as an "on" switch. The tricky ones are pin 4 "speed command" which should be a pulse-width modulation (PWM) signal to control the speed of the pump (simliar to the fuel pump control), and pin 5 "diagnostic" signal.

First, I'd check for proper power and ground on the chassis side of the harness for pins 1, 2, and 6. Then I'm thinking that if you ground pin 6 and apply 12v to pins 1 and 2, there's a 50/50 chance it will run the pump. If it doesn't do anything, try applying 12v (100% PWM) to pin 4 as well. If still no joy, time to tag in the dealer service.

Actually, you may want to read that whole thread. Some other info on diagnostics, Forscan, etc.

YMMV, professional driver on a closed course, not responsible for damage, injury, or death, no user serviceable parts inside, do not try at home.
 
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27
13
GA
Update - Got the car back. They replaced the diff cooler pump. I won't have the ability to test it until next season, unfortunately. Hopefully this resolves it.
Glad to hear it got replaced. Did they say anything about this? I only ask because I just installed the AWE Switchpath to close the valves when blackflagged but I wished the harness came with exhaust shielding but others haven't had issues yet so I suppose the clearance is what it is. Anyhow, yours doesn't really like look damage from the exhaust but more like someone probing it to test current.
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