Resolving the Hot Start Issue – Replacing the Crankshaft Position Sensor (CPS) 9177221.
Symptoms of a Hot Start Issue are when the car continuously cranks and refuses after a journey when the car gets to operating temperature, however, once cooled it is fine to crank and fire up.
When the ignition is switched on, the Trionic 7 EMS lights the CHECK ENGINE lamp and performs the function check. The fuel pump is activated for 1 second to build the fuel pressure, after which the EMS will await pulses from the Crankshaft Position Sensor, if this fails the EMS will disable the ignition and fuel injection. When the CPS Ohms resistance falls outside the operating perimeters, it activates the failsafe, according to WIS, the Sensor resistance should be 860±90 ohms.
My Saab 9-5 Aero 2.3 Turbo B235R had a hot start issue during the summer of 2020, where, if I switch off the engine when at optimum temperature and attempt to restart within a short timeframe, the car will crank and refuse to fire, however, if I let it rest for 45-60mins it was quite all right.
This was an intermittent issue and I experienced it no more than on three occasions, however, before it got worse I decided to replace the CPS in July with an aftermarket item as I was unable to source a Bosch part.
After replacing the sensor I never had any issues, I am very sure that the heat from the Turbo and CAT destroyed the CPS due to the close proximity to heat. The metal heatshield surrounding the CPS most probably has minimal impact on dispersing or deflecting the heat.
All you will need to replace the CPS is a T30 Torx for the CPS bolt a flat-head screwdriver to remove the wiring loom and a lot of patience.
Tightening torque, nut, and heat shield:
20 Nm (15 lbf ft) (up to and including engine no. 7011078)
21 Nm (16 lbf ft) (from and including engine no. 7011079)
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Car finally threw a code p0337 it was having hard starts and would die occasionally while idling when hot. Classic crank sensor symptoms so happy its a cheap and easy fix because I am about to sell this car.
Thanks for the video.
Thanks for the video. What exact CPS did You buy? has to be Bosch, or Valeo is ok too? Anyone tried other brands?
Is this the position/circuit a or b?
Would have been nice to see how you got the wiring unhooked as I cannot get mine to release either… Other than that, quite appreciated!
this is awesome. really shows where and how.
gonna go change mine now. thanks.
jizz…!
Thanks for your video, at least one know the exact position ( to abuse the hands on)
Thank you again!
well done lads, helped me finding and changing mine
It costs nothing to tell people what size the bolt is
Great video man , can you tell me where is the komputer located in that car ?
After removal, slice the bottom of the heat shield where the screw goes through approx 4 o'clock. Place new sensor in cavity, screw in bolt but do not tighten to allow heat shield to slide from top angle onto the screw. Tighten. This will make installation much easier.
LoL i wish i had slim hands and not these sausage fingers would had made it a lot easier for me, btw i have done 100d's of these
I had a hell of a time replacing this part. I had to bend the heat shield back and forth until it snapped off, otherwise you are blind to where the screw (T-30) is on the CPS. Even then, I had to use a very small air ratchet to remove the screw and a finger ratchet to screw it back on. Thanks for the video. It helped.
Nice video my friend
The cup.of coffee
to check for faulty CPS you can ohm it
Good work! thanks