850 engine sensor question

Tinamou · Nov 19th, 2021, 15:27

Are the crankshaft sensor and rpm sensor the same sensor with different names?

I'm getting blink code 131 from the OBD2 socket pin3, I think this is from the ignition system. In my Haynes manual this refers to "RPM sensor signal absent". I only see the code if I keep the engine running.

For sometime now I've been getting very brief, intermittent, engine cutout / loss of power. During these instances I occasionally see a very brief flash of the orange UP arrow. I think this is due to the cutout.

Luxobarge · Nov 19th, 2021, 16:27

Yes, same thing. When it stutters, do you see a flicker of the tacho needle too? This too is driven from the crank position sensor (CPS). Sounds like you have a dodgy one, you're lucky, when they go completely it won't leave a fault code, as the ECM simply thinks the engine isn't turning. It also leaves you with a total non-start situation, which can leave you stranded. I'd be changing it PDQ if it were me.

Cheers

Tinamou · Nov 20th, 2021, 08:14

Thank you, stuttering describes it perfectly. The garage said they had replaced the CPS, I will ask them. The engine starts and ticks over perfectly, its only when driven it happens.

This relates this post here I've only driven it to monitor and record data from various points on the engine, by chance I pulled over after a stutter and checked the blink code with the engine on. Then I found code 131, switching the ignition off / on cleared the code so I never saw it.

Nov 19th, 2021, 15:27	#1
Tinamou New Member Last Online: Jan 17th, 2024 11:28 Join Date: Sep 2021 Location: Oxford	850 engine sensor question Are the crankshaft sensor and rpm sensor the same sensor with different names? I'm getting blink code 131 from the OBD2 socket pin3, I think this is from the ignition system. In my Haynes manual this refers to "RPM sensor signal absent". I only see the code if I keep the engine running. For sometime now I've been getting very brief, intermittent, engine cutout / loss of power. During these instances I occasionally see a very brief flash of the orange UP arrow. I think this is due to the cutout. __________________ Volvo 850 1995 2435cc Petrol Automatic

Nov 19th, 2021, 16:27	#2
Luxobarge Premier Member Last Online: Yesterday 22:43 Join Date: Jan 2011 Location: Horne (Nr. Horley)	Yes, same thing. When it stutters, do you see a flicker of the tacho needle too? This too is driven from the crank position sensor (CPS). Sounds like you have a dodgy one, you're lucky, when they go completely it won't leave a fault code, as the ECM simply thinks the engine isn't turning. It also leaves you with a total non-start situation, which can leave you stranded. I'd be changing it PDQ if it were me. Cheers __________________ Some people are like Slinkies, they serve no useful purpose but they still bring a smile to your face when you push them downstairs.

Nov 20th, 2021, 08:14	#3
Tinamou New Member Last Online: Jan 17th, 2024 11:28 Join Date: Sep 2021 Location: Oxford	Thank you, stuttering describes it perfectly. The garage said they had replaced the CPS, I will ask them. The engine starts and ticks over perfectly, its only when driven it happens. This relates this post here I've only driven it to monitor and record data from various points on the engine, by chance I pulled over after a stutter and checked the blink code with the engine on. Then I found code 131, switching the ignition off / on cleared the code so I never saw it. __________________ Volvo 850 1995 2435cc Petrol Automatic

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