Mystery intermittent stall, no error codes

nascenta · Post by **nascenta** » 16 Aug 2011, 17:01

Help!!!
I have a '96 850 T5 with 330,000 km. While driving the engine will just cut out. When it happens, I've noticed that the shift arrow light comes on slightly before all the other dash lights. I recently changed the copper contacts in the pnp switch which stopped the problem for a couple of months, but now it is happening again. There are no error codes. The backup light comes on like it should when in reverse so I'm assuming that it is aligned properly. I'm wondering if the pnp switch is just worn out (as in the contacts inside that the copper touches), but why no error code (313)? Has anyone ever seen this, a bad component that doesn't get flagged by an error code?
Thanks

Post by **jblackburn** » 17 Aug 2011, 07:47

Has anyone ever seen this, a bad component that doesn't get flagged by an error code?

ALL the time

Does your car start back up immediately afterwards?

If it cuts off and doesn't like to start back up again for a few minutes, I would suspect a bad fuel pump relay. The cover to the upper fuse panel near your windshield can be removed with 4 T-25 Torx screws around the edges. Open it up and remove relay #103. Stick a jumper wire between pins 15 and 87. If it fires right back to life again, you just need to order a new relay.

nascenta · Post by **nascenta** » 19 Aug 2011, 23:55

Thanks for the tip. It does start up right away afterwards. I've gone ahead and replaced the relay so we'll see. I'll report back. In a few days

Post by **scoobycant** » 20 Aug 2011, 06:45

Have you ever replaced the crankshaft position sensor? My 98 V70R shut off about a dozen times over the course of a month without setting a code. Sometimes it would restart right away, sometimes it needed 5 minutes or so. Seemed to happen on really hot days (>90 deg). Finally got a code when it didn't stall. I replaced the sensor and hasn't stalled since.

nascenta · Post by **nascenta** » 21 Aug 2011, 14:16

I'm thinking that I have two problems at the same time. I replaced the fuel pump relay (103) and since then the vehicle hasn't stalled while driving. However, now it is not starting. Last night I turned it off and then went to start it up and got nothing. No interior lights, no sounds, nothing. Yet the battery is good (full charge). I boosted it (with jumper cables) and it started and got into my garage. There it sits. As I play with the key in the ignition the warning lights in the dash are sometimes not lit, sometimes they are weak and once in a while the lights are bright (like they should be) but they don't stay that way. In any case, the starter is not turning, the headlights aren't going on and the radio asks for the code suggesting that power has been cut off? Can the crankshaft position sensor (CPS) cause all this? I've replace the electrical connector portion of the ignition (a round plastic disk with short metal rods sticking out of it) but not the cylinder itself. Might the cylinder affect the flow of electricity somehow? I've also traced the grounding leads and found no corrosion, sanded, put some di-electric grease on them and reattached just in case. Any thoughts?

SteveDavis58 · Post by **SteveDavis58** » 21 Aug 2011, 20:51

that problem almost got me ran over. Mine would just cut off at speed & sometimes would not start on a cold start. Got progressively worse. Problem turned out to be in-tank fuel pump.
Steve

nascenta · Post by **nascenta** » 23 Aug 2011, 20:48

An update. I got out the multimeter and found that I had a resistance of 250 ohms between pin 1 (closest to the engine) and 3 (middle pin) on the CPS (cam position sensor). I had the ignition key in position II while fiddling around trying to touch something that would bring it to life and grounded pin 1 input (12 v) and the headlights when on and the starter spinned!!! Does this indicate a failed CPS? Even though no error codes? While the key was in position II there was 12 volts in all three input pins. Any advice?

robt · Post by **robt** » 24 Aug 2011, 00:50

jblackburn wrote:
Has anyone ever seen this, a bad component that doesn't get flagged by an error code?
ALL the time

Does your car start back up immediately afterwards?

If it cuts off and doesn't like to start back up again for a few minutes, I would suspect a bad fuel pump relay. The cover to the upper fuse panel near your windshield can be removed with 4 T-25 Torx screws around the edges. Open it up and remove relay #103. Stick a jumper wire between pins 15 and 87. If it fires right back to life again, you just need to order a new relay.

check vac line from fuel pressure reg

nascenta · Post by **nascenta** » 24 Aug 2011, 09:39

According to my wiring diagram, Pin 1 ends in the ecu pin A-18, Pin 3 ends in the ecu pin A-36, and pin 2 ends in ecu pin A-21. I pulled the ecu and checked for continuity in these wires. Got continuity in all three wires. I also disconnected the fuel pressure regulator vacuum hose and checked it by blowing into it. No leak. Stay posted.

nascenta · Post by **nascenta** » 12 Jan 2014, 08:12

It's been a while and I realized I never provided closure on this. It turned out that the pnp switch needed to be realigned. That's all! It was easy to do. The switch is just really sensitive to it's position on the transmission.