QuestionI have a 02 jeep grand Cherokee 4.0 that started acting like it was running
out of gas while driving ( but it was full). I pulled in the station and shut it
off. It wouldn't start back. Just turn over like it wasn't getting fuel. If you
sprayed a little starting fluid in it it would start and die. So I took it to be
fixed on a trailer. When I got it to the shop it would start now. So the shop
put on a new fuel pump. When I went to get it it immediately started tring
to die when driving. The shop then put a crank sensor on it. This seemed
to fix the problem. I drove home thirty miles everything was fine. I came in
the house for apps 15 minutes. Tried to start jeep and it wouldn't start until
the 3rd attept. When it did start at idle speed it tries to die. It will still only
start on the 3rd try. I have replaced the fuel pump, crank sensor, camshaft
position sensor, spark plugs, coil pack and cleaned the throttle body. I am
still getting the codes P0340, P0351 and P1391. What do I try now?
AnswerP0340-NO CAM SIGNAL AT PCM
POSSIBLE CAUSES
CRANK POSITION SENSOR SIGNAL
CHECKING INTERMITTENT CMP SIGNAL WITH LAB SCOPE
5 VOLT SUPPLY CIRCUIT SHORTED TO GROUND
5 VOLT SUPPLY CIRCUIT OPEN
5 VOLT SUPPLY CIRCUIT SHORTED TO VOLTAGE
CMP SENSOR SIGNAL CIRCUIT SHORTED GROUND
CMP SENSOR SIGNAL CIRCUIT OPEN
CMP SENSOR SIGNAL CIRCUIT SHORTED TO VOLTAGE
CMP SENSOR SIGNAL SHORTED TO 5 VOLT SUPPLY CIRCUIT
CAM POSITION SENSOR GROUND CIRCUIT OPEN
PCM - 5 VOLT SUPPLY
PCM - CMP SENSOR SIGNAL
CAMSHAFT POSITION SENSOR
P0351-IGNITION COIL #1 PRIMARY CIRCUIT
When Monitored: With battery voltage greater than 8 volts during engine cranking or
greater than 12 volts with engine running, engine rpm less than 2016, and none of the coils
in dwell when checked.
Set Condition: Peak current is not achieved with battery based dwell plus 1.5 msec of
diagnostic offset. It takes less than 3 seconds during cranking or up to 6 seconds while
running to set.
POSSIBLE CAUSES
INTERMITTENT CONDITION
ASD RELAY OUTPUT CIRCUIT OPEN
CAPACITOR(S) SHORTED TO GROUND
ASD OUTPUT CIRCUIT SHORTED TO GROUND
COIL ON PLUG
COIL DRIVER CIRCUIT SHORTED TO GROUND
COIL DRIVER CIRCUIT OPEN
POWERTRAIN CONTROL MODULE
P1391-INTERMITTENT LOSS OF CMP OR CKP
POSSIBLE CAUSES
CMP AND CKP OUT OF SYNC
CHECKING INTERMITTENT CMP SIGNAL WITH LAB
HARNESS INSPECTION
TONE WHEEL/PULSE RING INSPECTION
WIRING HARNESS INSPECTION
TONE WHEEL/PULSE RING INSPECTION
CHECKING INTERMITTENT CKP SIGNAL WITH LAB
CAMSHAFT POSITION SENSOR
CRANKSHAFT POSITION SENSOR
