I have a 2002 Jeep Grand Cherokee 4.0L with automatic transmission. Without warning it will die with no check engine light and no error code in memory. My first guess is the PCM or fuel pump but how can I tell which?
Thanks in advance for any assistance.
Does the vehicle restart after the stall?
When the vehicle stalls check to see if you have spark at the spark plugs.
If you don't have spark at the plugs the most common problem you might have is a bad crank sensor. It can make the engine stall and leave no codes or check engine light. The crank sensor is responsible for the spark signal.
If you have spark at the plugs then check the fuel pressure.
The first time it happened it died for about a half second while at highway speed and restarted without doing anything.
Second time I had stopped for a stop sign at the bottom of a hill, restarted immediately.
Third time was at the top of a hill, again, I stopped at a stop sign. Would not restart for about 10 minutes.
Since then I have not driven it more than a hundred yards. Have started it and allowed it to idle for 10 to 15 minutes in hopes of having it die and plug in the code scanner immediately without turning off the engine but to no avail.
I'll take a look into the crank sensor.
Get back to us with your results, we can diagnosis the problem further if needed.
Have not had the opportunity to replace the crank sensor yet. For the most part the Jeep is just sitting around. Went to move it yesterday and all was well. Went to move it this morning and it repeatedly cranked well but refused to start. My code scanner was not available so I could not check for errors. Gave it one last try, shifted to N then tried and it started right up. Don't know if this indicates anything.
A bit more information: The first and third times listed in an earlier comment the engine was fully warmed up. The second time, "at the bottom of the hill", was about a minute after starting the engine. This morning the engine was around 55 degrees F, the overnight low temperature. I have had sensor failures on other vehicles that were temperature related, if this is a sensor failure it must be close to terminal.
Last edited by 2002darkblue (5/25/2016 12:47 PM)
A code reader will not give you the values of sensors. A good scanner that has real time data can give you values of engine coolant sensor, air temp sensor, TPS switch, Map sensor, Baro sensor, engine rpm, crank sensor, cam sensor the list goes on.
If you know someone who has a good professional scan tool to scan your vehicle or go to your local certified mechanic or dealer and pay the diagnostic fee you can get the information you need to diagnosis the problem.
It could be temperature related or it could be another issue not letting the vehicle start.
When the engine won't start watch the engine RPM's, if the RPM's are not present during start up then it could be one indication that could be in the crank sensor circuit or the sensor itself.
Get back to me when you find out. We can diagnosis the issue from there.
My "scanner" is an AutoXray EZ-Scan 6000. I believe it will record most if not all of the information you've mentioned. Just used it last week and now it is AWOL. Thanks for the tip on the tach, that will help!
"This news just in"...P0320
No Crank Reference Signal at PCM
No reference signal (crankshaft position sensor) detected during engine cranking.
The bad news is, royal pain in the butt to get to, the good news is the fuel tank is almost full and I don't have to drop it.
Last edited by 2002darkblue (5/26/2016 12:15 AM)
So I finally got the ambition to lay across the top of the engine and snake my arm down into a black hole to position the new sensor into it's new home. Then, working through the hole on the transmission "hump" managed to feed the retaining bolt into place without cross threading it. Surprisingly little grease on my hands and arms with only one scrape on an elbow and no blood loss. For the first time in over two weeks the engine started up without much cranking and hopefully my problem is solved. Another hour or so to put the interior back together and I'll be back on the road. Time will tell if this was the only problem. Thanks again for your advice.
Finally found my AutoXray EZ Scan 6000.
Two new error codes.
Cleared them twice and they keep returning. Is there something likely to cause both to show up?
Update: Checked and found what I believe to be the Bank 2, Sensor 1 connector had come loose and plugged it back in. Now I have only the P0051 code.
Update #2, (final update?), after a number of drive, scan, clear cycles I just drove about 3 miles and no more fault codes. The CEL had been coming on after less than 1/10 mile.
Last edited by 2002darkblue (6/12/2016 4:18 PM)
Both codes are related to that one oxygen sensor. The P0051 is saying that the heater circuit is too low. This may come back again, if it does just replace the oxygen sensor Bank 2 sensor 1.