Car dies after getting to Temperature

1999 Cab, 3/98 build. A couple days ago I was driving home and the check engine light went on. When I got home and pulled into the driveway I shut off the car. I then tried to restart it with the check engine light on and It would not restart. It would turn over fine with no evidence of a week battery. So I hooked up my Durametric and code P1602 displayed which is Supply Voltage Open Circuit and code Airbag B05 Supply Voltage. So I cleared the codes and low and behold the car started. I put it in the garage and hooked up the charger to make sure the battery was fully charged and brought the battery to O'Reilly's the next day and the battery tested out fine. So I put the battery back in the car and took it for a test drive today. I put in a voltage meter in the cigarette light socket and drove it around the neighborhood and the voltage read from 13.5V plus or minus. About 20 minutes into the drive at a stop light with the engine idling at a stop light the car shut off and the check engine light appeared. Voltage on the meter was 12.4 when it shut off. Very strange since the battery tested positive 30 minutes earlier. When I got home after a tow and as soon as the driver left l check the voltage and it was 12.1V. So I tried starting the car and it started right up on the first turn of the key. Is the head temperature sensor on these as on my 1987 Carrera? It appears when the car gets to fully temperature either the alternator is not charging or at full temperature something causes an open circuit on the ground or positive side. Anyone have this experience? I am going to check all the ground tomorrow but as hoping for a short cut in my diagnosis. Any help would be appreciated . .

Sounds like the Crank Position Sensor is going out when hot. A very common failure. Does the tach needle bounce when cranking in a no start condition..? Can try spraying/soaking the CPS with brake clean when its hot and won't start. Lots of times the cooling effect of the brake clean will get it started.... jmo

I will check

Thank you

Will CPS cause a voltage drop ?

I think you are chasing a problem that isn't there with the alternator/ voltage. Your numbers for that sound fine with it being 13.5 running and 12.1 ish not running. Go after the crank or cam position sensor. The code you're getting does give me pause though. Check them again after this second non start. I am pretty sure there is a specific CPS code. But, this is a very common failure point. Let the battery issue go.

Will do thank you. I’ll check the code again and report back.

My car had the same problem. I had a cps code for CEL so I replaced mine and it�s been working fine now.

Quotes source post: 19992166

Electrical engineer here. You 100% have a corroded starter/alternator cable. The telltale evidence is the voltage drop as the car warms up. Part number 996-607-019-M100 The cable has two wires swedged together that connect to the starter. One cable goes to the alternator and the other goes to the battery. As the car heats up, the radiator fans come on and they draw current through the corroded cable, but the corroded part acts like a big resistor and the voltage through it drops. You see it at the voltmeter. The battery is not being charged and is being drained at that point which is why the voltage drops to 12.X and then the battery is fried. The design of the cable is poor and most drivers don't realize that the cable is keeping the battery from being charged and so they buy new batteries thinking that's the issue when it really is this dumb cable. Here is what it looks like fully corroded and fried:

thank you. Makes sense

Quotes source post: 19993044

Budy of mine has H2O in is license: H2O-KLR

For reference, when you have installed: 1) New battery; 2) New alternator; and 3) a new starter/generator cable, this is what the voltmeter will read when the engine is warm and the radiator fans are running. When the fans are not running, the meter is just north of 14V.

thanks again. I will tackle the project tomorrow.

Upate, unfortunately the cable wasn�t the problem. Be a life long CA must have a less corrosive environment. Look really clean and a non issue.

Could it be the CPS. I’m thinking the negative side will be as heathy as the positive side. Thoughts?

Quotes source post: 19998067

Sure it "could" be, just as numerous other things "could" be the cause. Testing the CPS(crank and cam) would need an oscilloscope to do it correctly. Very few people have access nor the ability to use one. So, you are relegated to loading up the parts cannon and throw stuff at it until you hit gold. People also spend lot's of attention to the positive leads of a battery, but often the grounds are neglected. It is easy to do and you might want to check the ground connection on the engine. It is on the passenger side. That needs to be clean and tight as well.

Quotes source post: 19998065

I see it looks fine, but the symptoms 100% match that cable being bad. I don't know anything else that would cause the voltage drop at temperature.

Quotes source post: 19992245

As said in the start of this thread,,, . If tach needle bounces when engine is cranking but not starting, its not the CPS. If tach needle does not bounce when cranking, CPS is bad. Or cps wiring is faulty. No scope needed. This might not be 100%, as other ecu/wiring problems could cause this, but thats not likely if this 'no start' just came out of no where, and no other damage to car/dme/ecu/wiring/fuses/ etc occurred. But so easy to see might as well look at it. And changing a cps is cheap and easy as far as 996 repairs go Many codes can pop up with a bad CPS that confuse. Seen a few CPS go bad and never leave a cel/fault code

I'll check that next, thank you.

Quotes source post: 19998277

All end of the "Y" cable looked good. But I haven't tested the car yet so we will find out. I will report back once I do. I will also check the the ground leads. Thank you.

So I took the car out for a test drive with the new cable, cleared ground cables at the engine and battery box. Drove it until to get hot, but before it reached full temperature I parked in the garage and sure enough after about a 40 run time it shut off. Tried starting but no luck. Cranks fine and strong like it want to start but no starting. Tach needle is not bouncing. How the 2 codes P1602 - Supply voltage open circuit; and P1531 - Camshaft adjustment bank 1. When it's running the charging voltage is around 13.8V +/- . Took the battery to the auto parts store and they said it passed.

Oh, so the problem is that it shuts off by itself and won't restart right away? I'm stumped.

Quotes source post: 20010782

No tach needle bounce when cranking means the dme is not seeing the crank spin, when it should.... 98.6% sure the problem is bad cps when it gets hot, (very common 996 problem) or its wiring/connectors. Check all the cps connectors, then change out the CPS. They are cheap and easy to change out.... https://www.pelicanparts.com/More_In...IaAsKrEALw_wcB

I agree with Allcool. I would follow his direction first. If this too fails, might be time to go back to basics. During an "event" of the gremlin raising its head. Get ready to check for spark and gas. Many ways to do this. Need to figure out if it's a fuel supply issue or a spark issue.

It seems that’s what we are down to. Thank you everyone. I’ll report back when I have more information.

Like Allcool says, lost of rpm bounce while cranking sounds very much like bad CPS, I've had a few bad CPS that never listed a fault code for CPS.

Quotes source post: 19998352

you are speaking about the "crank" and not the "camshaft" sensor correct?

Update, replaced the crank sensor and took it for a drive up to operating temperature for about 45 minutes so far so good. It did not die like before but still threw a p1531 code . The crank sensor lead did have 2 small cuts in the sheathing to the wires . So hopefully that was the cause of the engine quitting, here is a photo of the cut. Hard to see but present.

Thank you everyone for the input. I’ll update on the 1531 code next.

The 1531 is the bank 1 actuator issue. Can u read the "actual" can value with your scaner. It should jump when u rev past 3500 rpm. Also what r your cam deviations?

That is next on the list.

So to close the loop in this camshaft deviation is in the acceptable range +/- 2. The replacement of the crank position sensor solved the unexpected stalling problem. However, the source of the P1531 code is mystery and must be somehow be related to the the intermittent signal from the CPS. This is pure speculation of course. I have been driving for a week now and not issue with stalling when fully up to temperature.

No it has nothing to do the cps sensor. It has to do with variocam on bank one not actuating or the soleniod is failing. The piston is getting hung up due to failed o-rings and is sometimes not moving the variocam or the soleniod is not sending the signal. The only way to be sure is to log the "actual cam values" because its intermintant. The "cam deviation" value is taken over a long period if time and show an issue. Eventually the actuator fully jam or the soleniod will fully fail. U will most likely be pulling the cam cover in that bank to make the repair.

So far the code has not come back. I had BR Racing in Los Gatos investigate. They check the deviation and said it was within specification. So far now unless a code pops up again.

Fingers cross its fixed.....just minitor. If the variocam does go bad it will just stick open or close and cause a rough idle or sluggish accel.

let's hope so. thank you for your input.

Quotes source post: 20031173

Just a guess, but possibility you had 2 problems. Even though that is unlikely. 1) Bad CPS that is now fixed. 2) Like DJ says, cam timing actuator problems. OR, maybe the CPS when getting hot and either going open circuit or shorting out (or intermittently doing 1 of those or both for a second or 2 till it stalled out..?), caused the DME to read/interpet a bogus crank position and then compared it to the cam position sensor right before it stalled out, and found a *incorrect* 'deviation excess to trip a code...? just a wild guess.... You never got a CPS code, yet CPS was bad. Got to take some of these (1998 DME) codes with a few grains of salt imho because we never know how the DME might interpret a intermittent failure that affects many other different operations. Like you said wouldn't worry about it till it happens again. If or when it does, then you've got a pretty good idea whats going on. Glad the CPS got you going again...!!!

Quotes source post: 20032790

so far good. I think you summed it up.