Voltage regulator Recently replaced PCM [van wouldn't start, but would turn over] before that I replaced the crankshaft positioning sensor. The altenator is 6 months old [120amp], and put in a brand new battery. Only to have the battery go completely dead w/i a very short period. Had Auto Zone do their diagnostics on the charging system only to find out there is a problem with the voltage regulator. Within the PCM, but since my ignorance has surpassed the 10 day return window, to send it back would cost me the better part of $150.00. I am a single Grandfather on disability. I heard there is a kit to build a exterior regulator, bypassing the PCM?

DTC P0335 - Crankshaft Position Sensor A Circuit Malfunction
The crankshaft position sensor (CKP) measures crankshaft location and relays this information to the PCM (Powertrain Control Module). Depending on the vehicle, the PCM uses this crankshaft position information to time the spark properly or on some systems it is only for misfire detection and does not control spark timing. The CKP sensor is stationary and works in harmony with a reluctor ring (or toothed ring) that is attached to the crankshaft. As this reluctor ring passes in front of the CKP sensor, the magnetic field created by the CKP sensor is interrupted and this creates a square wave voltage signal that the PCM interprets as crankshaft position. If the PCM detects that there are no crankshaft pulses or if it sees a problem with the pulses on the output circuit, P0335 will set.

A P0335 "check engine light" code could be caused by:
Damaged CKP sensor connector
Damaged reluctor ring (missing teeth or not turning due to sheared-off keyway)
Sensor output open
Sensor output shorted to ground
Sensor output shorted to voltage
Failed crank sensor
Broken timing belt
Failed PCM

If you need additional details about test and solutions, just contact us in the Code Link.

Hope this helps; also keep in mind that your feedback is important and I'll appreciate your time and consideration if you leave some testimonial comment about this answer. Thank you for using Fixya, and have a nice day.

Jose.

Hi, it can be either of those or possibly a shorted condense or a bad crank sensor. First, I would check for battery voltage at the positive terminals of the coil when the key is on. If no voltage there, try disconnecting the condenser. If there is voltage, then check for AC voltage across the coil terminals while cranking the engine. If there is no AC voltage, the problem may be the crankshaft position sensor. The crankshaft position sensor is located next to the flywheel/torque converter. The computer is rarely the problem unless there was a short that caused undue current to flow.




Testing Crankshaft Position Sensor
2.4L Engine

1. Disconnect the sensor electrical connector. Connect an ohmmeter.
2. Measure the resistance between terminals 2 and 3, on the crankshaft position side of the connector. Specification should be 0.486-0.594 kohm at 68 degrees F.
3. If measured value is not within specification, replace the sensor.

1. Be sure that the CKPS and PCM connectors are connected.
2. Engine ON and monitor the signal waveform of the sensor on the scan tool. Check whether the waveform is synchronized with the crankshaft position sensor or not.
3. If the waveform signal is normal, substitute with a known good PCM and check for proper operation. If the problem is corrected replace the PCM.
4. If the waveform signal is not normal, substitute with a known good CMPS sensor and check for proper operation. If the problem is corrected replace the CMPS.

2.5L Engines

1. Disconnect the sensor electrical connector. Connect an ohmmeter.
2. Measure the resistance between terminals 2 and 3, on the crankshaft position side of the connector. Specification should be 0.486-0.594 kohm at 68 degrees F.
3. If measured value is not within specification, replace the sensor.

DTC P0340 - Camshaft Position Sensor Circuit Malfunction
This indicates that a problem was detected in the camshaft position sensor circuit. Since it says circuit, that means the problem could lie in any part of the circuit - the sensor itself, the wiring, or the PCM. Don't just replace the CPS (camshaft position sensor) and think that will definitely fix it.

Symptoms can include:
Hard starting or no start
Rough running / misfiring
Loss of engine power

A code P0340 could mean one or more of the following has happened:
a wire or connector in the circuit could be grounded/shorted/broken
the camshaft position sensor may have failed
the PCM may have failed
there exists an open circuit
the crankshaft position sensor may have failed


With a P0340 OBD-II trouble code, diagnosis can be tricky at times. Here are some things to try:
Visually inspect all the wiring and connectors in the circuit
Check for continuity in the circuit wiring
Check the operation (voltage) of the camshaft position sensor
Replace the camshaft position sensor as required
Check the crankshaft position circuit as well
Replace circuit wiring and/or connectors as required
Diagnose/replace the PCM as required


Monitor CMP sensor signal on a labscope looking for electrical noise that shows up on the pattern along with the CMP sensor Analog Current (AC) voltage sign wave signal.

Check timing belt alignment specific to the auxiliary shaft gear. There is a diamond on the gear that should align with a diamond on the rear belt cover just above the gear.

If electrical noise is present on the sensor signal, disconnect one coil pack at a time and disconnect the voltage regulator connection on the alternator to identify if the added electrical noise on the CMP signal pattern cleans up indicating the source of the electrical noise.

If no added electrical noise is present on the pattern and the timing gears are properly aligned, check the Dark Blue/Orange (DB/O) wire to verify it is not open between the sensor and PCM pin 85.

Also check the Grey/Red (GY/R) wire to verify it is providing a ground

In checking timing belt alignment, the auxiliary shaft sprocket has a diamond that should align with a diamond on the timing cover at the 12:00 position of the sprocket when the camshaft and crankshaft gears are at the top dead center position. If the Camshaft Position (CMP) sensor signal shows electrical noise on the labscope, disconnect the voltage regulator connection, and the coil packs individually to see if the electrical noise on the signal cleans up pinpointing the area of failure. If electrical noise cleans up when disconnecting a coil pack, remember that any of that pack's plug wires or the pack itself may be causing the noise.

Hope helps (remember to rate and comment this answer)..

what motor?

Is the PCM power relay activating? If yes, you should hear the fuel pump hum for 5 seconds when the key is turned to ON.

If yes, then check the crankshaft position sensor and camshaft position sensors to be sure they have output to the PCM.

The crankshaft position sensor:

• sends the powertrain control module a signal indicating crankshaft position.
• is essential for calculating spark timing.

Crankshaft Position Sensor (Integrated Ignition Systems) The crankshaft position (CKP) sensor is a magnetic transducer mounted on the engine block adjacent to a pulse wheel located on the crankshaft. By monitoring the crankshaft mounted pulse wheel, the CKP is the primary sensor for ignition information to the powertrain control module (PCM). The trigger wheel has a total of 35 teeth spaced 10 degrees apart with one empty space for a missing tooth. The 6.8L ten cylinder pulse wheel has 39 teeth spaced 9 degrees apart and one 9 degree empty space for a missing tooth. By monitoring the trigger wheel, the CKP indicates crankshaft position and speed information to the PCM. By monitoring the missing tooth, the CKP is also able to identify piston travel in order to synchronize the ignition system and provide a way of tracking the angular position of the crankshaft relative to fixed reference (Figure 23) .


Camshaft Position Sensor The camshaft position (CMP) sensor detects the position of the camshaft. The CMP sensor identifies when piston No. 1 is on its compression stroke. A signal is then sent to the powertrain control module (PCM) and used for synchronizing the firing of sequential fuel injectors. The Coil On Plug (COP) Ignition applications also use the CMP signal to select the proper ignition coil to fire. The input circuit to the PCM is referred to as the CMP input or circuit.
There are two types of CMP sensors: the three pin connector Hall-effect type sensor (Figure 20) and the two pin connector variable reluctance sensor (Figure 21).



A4 CHECK VREF VOLTAGE TO THROTTLE POSITION (TP) SENSOR

• Disconnect TP sensor.
• Key on, engine off.
• Measure voltage between VREF and SIG RTN circuit at the TP sensor harness connector. Refer to the schematic in Pinpoint Test DH .

Is voltage between 4.0 and 6.0 volts? -------- A17 CHECK PCM DRIVER TO COILS

• Connect incandescent test lamp between B+ and each coil driver circuit at the harness connector.
• Crank engine.

Does lamp blink consistently and brightly (one blink per engine revolution)?

P0400 - Exhaust Gas Recirculation Flow Malfunction
The exhaust gas recirculation (EGR) valve is vacuum controlled valve that regulates the amount of exhaust gases that re-enter the cylinders. The powertrain control module (PCM) determines how much based on engine load, temp, and other conditions. If the PCM detects that the amount of exhaust gases entering the cylinder were insufficient or non-existent, this code is set.

Symptoms: No symptoms will likely be noticed by the driver other than the MIL (malfunction indicator lamp). However, non visible symptoms will be increased combustion temperature and increased Nox emissions.

Causes: A code P0400 may mean that one or more of the following has happened:
Plugged EGR passage which restricts the flow of exhaust gasses
Faulty EGR solenoid
Faulty EGR solenoid wiring/harness
Vacuum lines damaged/disconnected to the EGR valve solenoid or to the EGR valve
Faulty EGR valve

Possible Solutions: Since EGR valve designs are different, no one test will suffice:
Using a scan tool, operate the EGR valve with the engine running. If the engine stumbles, the problem was likely intermittent wiring problem or intermittent blockage problem
If engine doesn't stumble, operate the EGR valve manually, if possible. If engine doesn't stumble and die, the ports are likely plugged. Removal of valve and cleaning of all ports will be required
Checking of solenoid can only usually be done with a scan tool, because most solenoids operate with a duty cycle of voltage, rather than constant voltage
Check all vacuum lines, hoses, etc for any damage
Visually inspect the solenoid harness and the solenoid for damage
Replace EGR valve



P0385 - Crankshaft Position Sensor B Circuit Malfunction
The crankshaft position sensor (CKP) measures crankshaft location and relays this information to the PCM (Powertrain Control Module). Depending on the vehicle, the PCM uses this crankshaft position information to time the spark properly or on some systems it is only for misfire detection and does not control spark timing. The CKP sensor is stationary and works in harmony with a reluctor ring (or toothed ring) that is attached to the crankshaft. As this reluctor ring passes in front of the CKP sensor, the magnetic field created by the CKP sensor is interrupted and this creates a square wave voltage signal that the PCM interprets as crankshaft position. If the PCM detects that there are no crankshaft pulses or if it sees a problem with the pulses on the output circuit, P0385 will set.

Symptoms:
NOTE: If the crank sensor is used only for misfire detection and NOT spark timing (this varies with the vehicle), the vehicle should start and run with MIL (Malfunction indicator lamp) illumination. Also, some vehicles require several key cycles to illuminate the MIL. If this is the case, there may be no MIL illumination until the problem often enough over time. If the crank sensor is used for BOTH misfire detection and spark timing, the vehicle may or may not start. Symptoms may include:

Vehicle may not start (see above)
Vehicle may run rough or misfire
MIL illumination

Causes: A P0385 "check engine light" code could be caused by:
Damaged CKP sensor connector
Damaged reluctor ring (missing teeth or not turning due to sheared-off keyway)
Sensor output open
Sensor output shorted to ground
Sensor output shorted to voltage
Failed crank sensor
Failed PCM

Possible Solutions:
Using a scan tool, check if, when engine is running or cranking, that there is an RPM signal.
If there is no RPM reading, then visually inspect the crank Sensor Bnd connector for any damage and repair as necessary. If there is no visible damage, and you have access to a scope, you could check the CKP 5 Volt square wave pattern. If you do not, then, obtain a resistance reading of your crank sensor from a repair manual. (There are so many different types of crank sensors that there's no way to put here which resistance reading is correct). Then check the resistance of the CKP sensor by disconnecting the Sensor Bnd measuring resistance of the sensor. (It is best to check resistance readings from the PCM connector. This rules out any wiring problems from the start. But it does require some mechanical skill and shouldn't be performed if you\'re not familiar with automobile electrical systems). Is the sensor within resistance specs?
If not, replace the CKP sensor. If so, recheck resistance reading from the PCM connector. Is the reading still okay?
If not, repair open or short in the wiring to the crank Sensor Bnd re-check. If the reading is okay, the problem is intermittent or the PCM may be at fault. Try reconnecting and checking for RPM signal again. If there is now an RPM signal, wiggle test the wiring harness to try and induce the fault.

This code is basically identical to P0335. This code P0385 refers to Crankshaft Posistion Sensor "B", whereas P0335 refers to Crankshaft Position Sensor "A". If you have the code P0385, your vehicle is equipped with two crank sensors (CPS). Other crank sensor codes include P0016, P0017, P0018, P0019, P0335, P0336, P0337, P0338, P0339, P0385, P0386, P0387, P0388, and P0389.


Hope this helps.

(this is for others who may be viewing this problem)
P1594 = charging system voltage is too high
P0320 = crankshaft position sensor (CKP)/engine speed (RPM) sensor-circuit malfunction
P0463 = fuel level sensor circuit, high output
P1391 = intermittent loss of CMP (camshaft position) or CKP (crank position) sensor

Probably start with changing the crank sensor. But keep in mind that the high charging system voltage may be causing the other electrical sensor problems. The voltage regulator (probably located internally in the alternator) is not regulating voltage properly. So changing the alternator may be needed as well. Price the parts and start with replacing the less expensive first.

Hello it is not easy to use a computer with a 4 year old constantly trying to get your attention.Anyhow i said disconnect your battery wait 5 minutes to reboot the computer i have gone through your situation a dozen times if it doesn't start it should trip your check engine light and you will be able to scan and retrieve keep me posted.John

No-Start Diagnosis
The diagnostic procedure for EI (electronic ignition) systems varies depending on the vehicle make and model year. Always follow the procedure recommended in the vehicle manufacturer's service manual.
The following procedure is based on Chrysler EI systems. The crankshaft timing sensor and camshaft reference sensor in these systems are modified Hall-effect switches.
If a crank or cam sensor fails, the engine will not start. both of these sensor circuits can be checked with a voltmeter or lab scope.
If the sensors are receiving the correct amount of voltage and have good low-resistance ground circuits, their output should be a pulsing digital signal or voltmeter reading while the engine is cranking.
If any of these conditions do not exist, the circuit needs to be repaired or the sensor needs to be replaced. When the engine fails to start, follow these steps:

1. Check for fault codes 11 and 43.
   • Code 11, "Ignition Reference Signal," could be caused by a defective camshaft reference signal or crankshaft timing sensor signal.
   • Code 43 is caused by low primary current in coil number 1, 2 or 3.
2. With the engine cranking, check the voltage from the orange wire to ground on the crankshaft timing sensor and the camshaft reference sensor. Crankshaft timing and camshaft reference sensor terminals.
   • Over 7V is satisfactory.
   • If the voltage is less than specified, repeat the test with the voltmeter connected from PCM (powertrain control module) terminal 7 to ground.
   • If the voltage is satisfactory at terminal 7 but low at the sensor orange wire, repair the open circuit or high resistance in the orange wire.
   • If the voltage is low at terminal 7, the PCM may need replacement.
     • Be sure 12V are supplied to the PCM terminal 3 with the ignition switch off or on, and 12 V must be supplied to PCM terminal 9 with the ignition switch on.
     • Check PCM ground connections on terminals 11 and 12 before PCM replacement.
3. With the ignition switch on, check the voltage drop across the ground circuit (black/light blue wire) on the crankshaft timing sensor and the camshaft reference sensor.
   • A reading below 0.2V is satisfactory.

NOTE When using a digital voltmeter to check a crankshaft or camshaft sensor signal, crank the engine a very small amount at a time and observe the voltmeter. The voltmeter reading should cycle from almost 0 volts to a highter voltage of about 5 volts. Since digital voltmeters do not react instantly, it is difficult to see the change in voltmeter reading if the engine is cranked continually.

1. If the readings in the previous two steps are satisfactory, connect a lab scope or digital voltmeter from the gray/black wire on the crankshaft timing sensor and the tan/yellow wire on the camshaft reference sensor to ground. Lab scope patterns from the camshaft and crankshaft position sensors.
   • When the engine is cranking, a digital pattern should be displayed or the voltmeter should cycle between 0 and 5 volts.
   • If the voltage does not cycle, sensor replacement is required.
   • Each sensor voltage signal should cycle from low voltage to high voltage as the engine is cranked.

A no-start condition can occur if the PCM "locks up."

• In step 2 above, if 0 volts is indicated the PCM may be faulty or it may be locked up.
• If the PCM is locked up it will not store a fault code for the reason.
• Basically, the PCM will lock up when it goes into a safeguard routine if the 9-volt or 5-volt reference voltage shorts to ground. This shuts down the PCM to protect it. Since it shuts down, no DTCs (Diagnostic trouble code) are stored.
• The engine will not start as long as the ground is present. An intermittent ground will cause the engine to stop running.
• Attempting to restart the engine without cycling the ignition switch to the full LOCK position will not start the engine, even if the ground is lifted.
  • Cycle the ignition switch to the LOCK position and wait about 5 to 10 seconds.
  • If the ground is lifted, the PCM will reset and the engine will start and run until the ground occurs again.
• On 1996 and new SBEC III and JTEC engine controllers, there are two 5-volt reference signals. The sensors that require 5 volts are separated, thus If this signal shorts to ground the engine will still stop running, but for the first time a DTC can be set.
• Also note, if the 9-volt reference voltage is opened, there will be no DTC stored for the crankshaft or camshaft positions sensors. With an open circuit the PCM cannot tell if the engine is cranking or not. The diagnostic routing does not begin until the PCM senses engine cranking.

Sounds like an AUTOMATIC SHUTDOWN (ASD) RELAY problem. Fairly common on the Caravan.
Heres a brief overview of the ASD.
The Powertrain Control Module (PCM) operates the Auto Shutdown (ASD) relay by switching the ground path on and off.
The ASD relay supplies battery voltage to the fuel injectors, electronic ignition coil and the heating elements in the oxygen sensors.
The PCM controls the relay by switching the ground path for the solenoid side of the relay on and off. The PCM turns the ground path off when the ignition switch is in the Off position unless the 02 Heater Monitor test is being run. Refer to On-Board Diagnostics. When the ignition switch is in the On or Crank position, the PCM monitors the crankshaft position sensor and camshaft position sensor signals to determine engine speed and ignition timing (coil dwell). If the PCM does not receive the crankshaft position sensor and camshaft position sensor signals when the ignition switch is in the Run position, it will de-energize the ASD relay.
The ASD relay is located in the Power Distribution Center (PDC). The PDC is located on the driver's side inner fender well Power Distribution Center . A label on the underside of the PDC cover identifies the relays and fuses in the PDC
Check for good ground.
Good luck...i hope this helps, please rate me a fixya.

Is the PCM - turning on the fuel pump ? If there are not any anti-theft system problems and the engine computer see's a input voltage signal from the Transmission range switch that the vehicle is in park or neutral and it sees a input from the crankshaft position sensor it will supply a ground to energize the fuel pump relay .

Is there a fuel regulator? NO there is no regulator . Watch this video ! GM Fuel Pump Relay Testing
Don't guess ,test !