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chris99 Newbie
Joined: 04 Jun 2023 Posts: 9 Location: Notts
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Posted: Sun Jun 04, 2023 15:30 Post subject: Pajero Pinin 1.8 GDI Auto - Gearbox wiring question |
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Hi everyone.
I am getting no output from three sensors on the auto gearbox: input shaft speed, output shaft speed and fluid temperature. These three sensors share a common wiring plug (labelled B03 in the electrical manual). The manual shows 2 pins for each plug (ground and return voltage) but the sensors have three pins (presumably a 12V feed too). Does anyone know where this 12V feed comes from? All 9 pins in the B03 plug are accounted for (two for each of these sensors and one for each of the solenoids).
Any help will be very gratefully received. I am pulling my hair out!
Thanks
Chris |
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Posted: Sun Jun 04, 2023 15:30 Post subject: Google Ads keep the POCUK free to join! |
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chris99 Newbie
Joined: 04 Jun 2023 Posts: 9 Location: Notts
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Posted: Mon Jun 05, 2023 12:25 Post subject: |
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UPDATE: Looks like I was mistaken. When I search online for "input shaft speed sensor" for my Pajero Pinin 1.8 GDI Auto (H66W), all results show 3-pin sensors. However, crawling under the gearbox confirms that they are 2-pin sensors.
Now my question is, does anybody know the part number for these 2-pin sensors? I can't find them anywhere online.
As always, grateful for any insight.
Chris |
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iam_TJ LifeTime Member
Joined: 10 Apr 2013 Posts: 351 Location: Europe
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Posted: Tue Jun 06, 2023 16:02 Post subject: |
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Are you sure one of the pins is ground? I would think it more likely there is a 12V feed and a signal, and the ground is through the chassis - but my 2003 Shogun LWB 3.5GDi with 5-speed auto workshop manuals don't/won't cover your system so I cannot check.
The fact you report all 3 sensors not returning a signal might also suggest a shared ground is the common fault.
If you can extract and share the page showing the circuit diagram I can compare with mine if that might help.
Are you able to share a link to the exact model code of your H66W on megazip.net since there are several H66W variations; it looks like the gearbox is 4-speed ? |
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chris99 Newbie
Joined: 04 Jun 2023 Posts: 9 Location: Notts
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Posted: Tue Jun 06, 2023 16:55 Post subject: |
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Hi TJ
Thanks for the reply. I am starting to confuse myself with some of the multitester results.
I am in the process of writing all my findings down and comparing them to the circuit diagrams. I will try to post some images soon.
Thanks again
Chris |
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chris99 Newbie
Joined: 04 Jun 2023 Posts: 9 Location: Notts
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Posted: Tue Jun 06, 2023 19:25 Post subject: |
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Hi TJ
If I can give you a little background...
I bought the Pajero very cheap because the owner said it was stuck in 3rd gear (when in DRIVE) but, having looked into the gearbox documentation, it seems it is in fail-safe mode:
L 1st gear only
2 2nd gear only
D 4th gear only
R Reverse
N Neutral
P Park
I first suspected the A/T ECU but, having taken it off and inspected the circuit board visually, there is no sign of capacitor-bloating or overheating, so I started to wonder about the values it was receiving. I tested what I could according to the checklist attached and I have highlightd the unexpected results in red.
I did think, as you mentioned, that it may be an earthing fault but it is not one I can find.
I have tested some pins for continuity (concentrating on the input shaft speed sensor as it is easiest to access). Results as below:
Pin 15 - sensor terminal on gearbox = Continuity
Pin 16 - sensor terminal on gearbox = Continuity
Pin 15 - earth = Open circuit
Pin 16 - earth = Open circuit
Pin 15 - Pin 16 = Open circuit
Gearbox housing - earth = Continuity
The other image attached shows the connections between the sensors and the A/T ECU.
One more thing that may or may not be relevant... The Neutral LED does not light on the dashboard display. I did try applying a 12V feed dirctly to solenoid valve 1 and I could hear it click, and the Neutral LED lit up, despite being in DRIVE.
If you can get your head around the above and offer any insight, please don't hesitate to get back to me.
Thanks and bet wishes
Chris |
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chris99 Newbie
Joined: 04 Jun 2023 Posts: 9 Location: Notts
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Posted: Tue Jun 06, 2023 19:29 Post subject: |
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Sorry, unable to add attachments |
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chris99 Newbie
Joined: 04 Jun 2023 Posts: 9 Location: Notts
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Posted: Tue Jun 06, 2023 19:38 Post subject: |
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Can't even post a link to a google drive where attachments are!!! |
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chris99 Newbie
Joined: 04 Jun 2023 Posts: 9 Location: Notts
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Posted: Wed Jun 07, 2023 15:57 Post subject: |
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Hi TJ. I am just north of the City Centre. I'm afraid every time I try to post an attachment or reply to a PM, the forum tells me I can't because I am a new user
Chris |
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chris99 Newbie
Joined: 04 Jun 2023 Posts: 9 Location: Notts
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Posted: Wed Jun 21, 2023 12:10 Post subject: |
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Hi all
Just an update in case anyone was wondering or has similar issues...
I had to replace the battery as it wouldn't hold a charge and, rather strangely, after I put the new battery on, all the gearbox sensors started returning the correct reading, both for voltage and resistance. As the gearbox speed sensors are permanent magnet type, and they generate their own AC current with their own + and - poles, I can't work out how changing the battery would affect this - but I can't argue with what I witnessed!
There was still no output from the pins on the TCM that should control the gearbox solenoids so I decided to re-examine the TCM. I took photos of the circuit board and enlarged them on the computer and found a hair-line crack running across the board close to where the plug is soldered. Not being skilled enough to repair this, I started looking into replacing the TCM.
Just to be sure that there wasn't an issue with the gearbox solenoids, I connected the O/D Off button directly to the relevant pins (with the TCM unplugged) so that I could test that they activated when I pressed the button (keep your speed low if you try this at home). The solenoids worked as they should when they received a voltage so it was looking more and more like the TCM.
The part number for my model is MR377379 and the only examples I could find on the net were overseas and in the region of £600 - £1000. By chance I spotted a similar looking unit on eBay (part number MR389246) with an identical looking plug. It turned out that this part was from a 2000 model (mine is 1998) but I ordered it anyway because I reckoned the asking price of £35 was worth a gamble.
Credit to Mitzy Bitz who posted the item the same day and it was with me less than 24 hours after purchase.
Anyway, the TCM arrived and it was identical to the old one. I plugged it in and it worked perfectly. The gearbox works a dream
Hope this helps anyone who having similar issues.
Chris |
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