Help! P1317 CODE, Spark Plug Misfire Detection Module in my 1995 NSX.

charlee · 17 March 2015

Hello,

While driving today, CEL and TCS light came on. Came home and tested for codes and it show P1317. After checking through all the threads, it shows the Spark Plug Misfire Detection Module to be the culprit. My car drives fine and has no issues.

This part is located right next to the alternator with two green plugs at teach end. The part number is 37950-PR7-A31.

I was wondering if anyone knows how I can check the functionality of this part. If not, I am hoping someone was willing to lend me their spare or one off their car so I can check the ohm readings with different combinations of pins from this module to compare to mine. I am looking to buy if you have one to sell.

You can remove this module using 10mm socket to remove two bolts and disconnecting both plugs. Should be under 3 minutes to remove it. Once your module arrives, I can have it shipped back to you within 24 hours. Your help is much appreciated.

Any help/info on this issue is also much appreciated.

Caroline-NSX · 17 March 2015

Coil pack. Check each coilpack by removing the coil cover and unplug one by one and if it doesnt make you engine shake then its that one. GL!

angus · 17 March 2015

I have a brand new unit to sell, I bought it only to test my car.

Old Guy · 17 March 2015

This code applies to the portion of the module that monitors the rear cylinder bank. Check the grounding of the module and look for damaged wiring on the connections to the coils on the rear cylinder bank. Make sure that the connectors on the rear coils are secure and clean. Otherwise, I think troubleshooting is pretty much 'replace with a known good module'.

charlee · 17 March 2015

Old Guy said:
This code applies to the portion of the module that monitors the rear cylinder bank. Check the grounding of the module and look for damaged wiring on the connections to the coils on the rear cylinder bank. Make sure that the connectors on the rear coils are secure and clean. Otherwise, I think troubleshooting is pretty much 'replace with a known good module'.

Thank you for this feedback. I was afraid of this; but wanted to make sure no stones are left unturned.

Larry Bastanza · 17 March 2015

Old Guy said:
This code applies to the portion of the module that monitors the rear cylinder bank. Check the grounding of the module and look for damaged wiring on the connections to the coils on the rear cylinder bank. Make sure that the connectors on the rear coils are secure and clean. Otherwise, I think troubleshooting is pretty much 'replace with a known good module'.

100% agreed

ralph cerbone · 18 March 2015

Old Guy said:
This code applies to the portion of the module that monitors the rear cylinder bank. Check the grounding of the module and look for damaged wiring on the connections to the coils on the rear cylinder bank. Make sure that the connectors on the rear coils are secure and clean. Otherwise, I think troubleshooting is pretty much 'replace with a known good module'.

had the same code ,it was the ground wires at the mounting base of module . the eye terminal for the ground wires was broke ,simple fix.hope this helps

charlee · 21 March 2015

ARGH! Cheapest is $509.xx plus shipping!

Andyrew500 · 1 September 2016

Charlee, Did you ever find a solution to this? My 96 also threw a P1317 - Misfire Detection Unit.

My MDU prints a part number of 37950-PR7-A31 but all the MDUs I've found are from newer NSX with a part number of 37950-P56-A01. Does anyone know if these parts are interchangeable?

Thanks,
Andrew

Old Guy · 1 September 2016

I am thinking; but, don't know for sure that you might have an orphan. The later part # applies to 1997 and later. If you can find a wiring diagram for your 1995 and a 1997 or later car, compare the pin outs / connections for the mis fire detection unit. If the pin outs are identical, then the newer module might be the same as the later module. If the pin outs or the connections have changed, then you know that you are definitely out of luck.

Of course, getting a response from somebody else who has actually gone through this would be much more useful than my musings :smile:!

Andyrew500 · 1 September 2016

I'm waiting on pulling the trigger for the latter part number as I'm hoping someone has had this experience and can confirm the compatibility.

The newer 97+ MDU is $70 and the discontinued 95-96 MDU is $650+... Another reason for me to upgrade to NA2

I did go back out this morning and dry up the water collected underneath the coil cover. Dried the plug holes, wiped down the coil packs, put everything back together, cleared the code and watched it come right back.

Old Guy · 2 September 2016

I would check the price again (unless it is used). At that price, I would snap that MDU up just to resell it, even if it didn't fit. The discounted retail price is more like $330.

http://www.oemacuraparts.com/acura/...unit-4-scat/?part_name=detection-unit-misfire

If you have the service manual for your year you can go through the diagnostic steps for the MDU. Its mostly about testing the wiring between the MDU and the ECU. There is no diagnostic test for the MDU proper. The MDU does not affect the function of the engine. If you cannot find a suitable MDU, with some creativity you could probably figure out how to fake the output of the MDU so that the ECU does not display a code even though the MDU is no longer functional.

JD Cross · 2 September 2016

The part for a 1996 unit is showing on oemacuraparts.com for $489.
http://www.oemacuraparts.com/auto-p...l-exhaust-heater-fuel-cat/control-unit-4-scat

Bram · 3 September 2016

Guys, the 1996 - 2004 RL, have these same units, therefore you can get these at the Junk yard for about $10.00
Easy to remove too, all you need is a 10mm wrench
Bram

Old Guy · 3 September 2016

Also used on some TLs; but, that is the later part #, not the 1995-97 NSX part #. However, it would be a cheap way of getting the later part and finding out whether the pin arrangement matches the early part.

Andyrew500 · 7 September 2016

For the benefit of the community, I'm happy to report back that the later newer part for 97+NSX and the 96+ RL does work on 95-96 NSX (it was $30 and I didn't have much to lose). Pinouts were the same, connectors plugged right in, and bolted right back into place. Cleared the check engine light and never came back.

Felt good to go back out for a drive knowing it's running healthy.

charlee · 4 May 2018

Replaced with a used Spark Plug Misfire Detection Module in 2015 from a 2001 RL donor car from junkyard.

Car drove great the past 3 years without any issues.

Just got a p1200 p1201 p1202 p1203 p1204 p1205 p1206 p1304

changed out plugs and coil packs as it was time anyways.

DTC remained and problem continues.

Just visited the junk yard and got another module.

Will test tonight. Crossing my fingers.

ralph cerbone · 5 May 2018

Had same problem , don't start replacing parts , look at the ground terminals at the retaining bolt ,the wire breaks after the terminal ,hope this helps

charlee · 20 May 2018

Problem solved. The igniter was the culprit.

AcuraNSX · 22 May 2018

How much was it to fix? Did you buy a new igniter, or a junkyard other Acura part? What is the part number for future knowledge. Thanks!

Help! P1317 CODE, Spark Plug Misfire Detection Module in my 1995 NSX.

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