1996 Chrysler Voyager 3,3 I think PCM is broken. I measured that 3 and 6 cylinders pin(2) are connecting to ground pin(10). When I cut that wire (3 and 6 cyl.) which goes from PCM to coil engine will start with 4 cylinders but when I connect that wire (that I cut before) the engine won't start at all. What's the problem?What's your problem?

You can see the ground wire for cylinders two and 5, it's the driver. Might be something wrong with wire connector--wire circuit--or pcm driver has a problem? Just a thought.

New PCM plugs and wires? hun?
new harness ,why? in a fire or wreck? running off road?
or did you mean, new PCM, new spark wires, and all new 02s sensors' It wont be a bad PCM , sorry, 99% are good.
P0132
the PCM never lies. it measure this and does a test and if it fails there is a circuit fault.
the why to understand, DTCs (have a FSM factory serv. manual)
and read how the test works. or do the tests it tells you do to
to discover true cause)
i have this car v6 3.8L: and 6speed and the FSM, book.
verbatim.
O2 SENSOR 1/1 CIRCUIT HIGH
1/1 means bank 1 , front sensor (upsteam)
bank one means right bank, cylinder 1 side.
what does HIGH mean?

what is not clear is which side is failing, heater or CELL
this test is the CELL pin (oxy out)
pin 4.
the test (called a monitor) finds that pin 4 is stuck at 5v.
the o2 must be 0 to 1volt at all times.
if stuck at 5vdc then the ground is open to CELL pin 3 (wire cut)
or the 02 sensors is bad. (open)
do you know how to back probe? a skill that is must for all modern cars. use needles with your meter. (DMM) (leather needles work in a pinch sold at walfart for 1buck) needle probes are 10x better
key on and back probe pin 4, if at 5vdc or more(or near) it's wrong.
btw page 2891 shows what to do in the FSM. yah 7000 pages.
I think this pin floats to 5v if the wire is cut.

fail 2 is that pin 4 is shorted to voltage ,well , the heater runs off
of 12v and all cars (bad service) the 2 wires melt and short.

here ill list all 4 pins (key on)
1- 12v heater.
2- ground
3 - ecu quite ground to 02 (cell minus)
4- CELL + out (this is the oxy signal)

pin 4 must not be at 5v or 12v, but 0 to 1 volts.
at key on or running.


one more FSM quote
Measure the voltage in reference to ground, not the (K902) O2 Return Upstream circuit.

that means pin 3 to 4, is measured for best accuracy
but 5vdc or 12vdc is gross wrong .

if the o2 is new (is)
then this quote covers most fails on most cars
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact
in the Oxygen Sensor and Powertrain Control Module connectors.

here is the wiring.
if you need more photos full size or more tests.
or have questions, ask, i'm a retired ET, (controls systems , PLCs +)







see FSM here
on CD (best of best)

https://www.techauthority.com/en-US/Pages/FacetSearchResults.aspx?make=Jeep&year=2008&model=WRANGLER+UNLIMITED+RUBICON+4X4&engine=3.8L+V6+%28SMPI%29&producttype=Service+Manuals&ptCatId=3083

on most PCMs the PCM passes ground (input to PCM) out to the sensors. so if that ground is bad all are.
this is done on purpose, so the PCM can measure ground errors
and adjust sensor readings accordingly.
now Ill look yours up. since you stated its a 4.7L , most poster here
have not a clue to what is under hood.
my guess is the map is reading wrong?????????????
HINT1: when measuring ground attach your DMM to the battery minus
post and it will read 0 to 0.5v max for ground.
what did you read, as you said its not GETTING ground.
so what was the reading? 12v?
i take it you work with FSM/s and its schematics.
see chapter 8w-30 (wiring , Fuel-------) page 16-18
http://www.jeep4x4center.com/knowledge-base/index.htm?utm_source=cj#service

see that page.? page 17 is best.
see the 3 pins?
PCM pin 4 is ground to MAP pin 1. 0volts
PCM pin 17 is 5vdc power supply to Map and most be 5v (+- .25v)
PCM pin 27 is map out sig to PCM, (baro measurements)


the PCM master grounds (input)
are C1 pin 31 and 32.
they must read 0v to battery minus. KEY ON. or running.

page 8w30-6 see that.

wish i had the full symptoms. , no start, runs bad. what?

02 GC 4.7L V8. KEY ON< or RUNNING? we cant guess that.
why not post the symptoms, so we can REALLY HELP YOU.
GOT DTC's what are they,. scan it yet, if not?, why not scan it.?
my guess is you are working FSM free? none.?
MAP. (manifold air pressure or BARO) top front of intake plenum man.

2 fuses drawing, what does that mean?
all fuses draw current.
why not post symptoms, ???????????

the fsm shows the MAP readings and vacuum and voltage output
chart, the MAP is BARO SENSOR, CALLED A 1 BAR BARO.
in simple terms it measures plenum vacuum and the PCM injects
based on that and on IAT plenum air temperatures.
with 2 sensors this engine measure AIR flow through the system.

the PCM creates 5vdc called 5vREF. The PCM has a regulator inside
the PCM to creates 5v, for the 4 external sensors.
TPS, MAP, Crank and Cam sensors. all run off 5vdc power.

YOUR map has 3 pins,
1 blk /Lb is ground from PCM. (black, light blue?)
2- output color DG/RD (darkgreen-red) bingo, sensor output.
3- orange, 5vdc all time key on.

weather and altitude changes MAP readings. ask for the rules.

Baro means barometer.
its and electronic barometer. or Baro for short.

here is cheat sheet (HG is standard mechanics, vacuum tool called relative vacuum )
The voltage is inversely proportional to Vacuum. (relative)
HG " volts. (DMM backprobing conn.)
0 = 4.8v
5 = 3.9v
10 = 3.1v
15 = 2.1v
20 = 1.1v
up to
hard
vacuum
28"HG = 0.5 (radical deceleration, in gear, throttle cut, down hill)


http://troubleshootmyvehicle.com/chrysler/3.9L-5.2L-5.9L/how-to-test-the-map-sensor-2

do not use my numbers as verbatim, get your own FSM
and see the chart for your sensor on your engine.

keep in mind the ECU provides the ground to this sensor.
so measure ground on the sensor to the battery, minus.
should be less than 0.5vdc.
then measure 5v, on the 5vdc pin, yes, good.
then output,
this is the correct order, sensors can not run, with bad power.
period.

does engine run?
dose enigine pull (hand gauge) 20"HG it idle, if way lower, there can
be burned intake valves.. if the vacuum pulsed badly that too
is bad valves. the ECU can not run a bad engine., not that bad.
The ecu can only compensate for normal wear, not dead cylinders.

Test procedure:


1. Test powers and grounds at the Powertrain Control Module (PCM) on the C1 connector. Pins 2 and 22 are power, then check pins 31 and 32 for ground.

2. Next, test the 5 volt power supplies at pin 17 of the C1 connector and pin 31 of the C2 or middle connector for shorts to ground. Sensors on the circuit are the Camshaft Position (CMP) sensor, Crankshaft Position (CKP) sensor, Throttle Position Sensor (TPS), Manifold Absolute Pressure (MAP) sensor and Vehicle Speed Sensor (VSS).

3. Unplug the sensors on the 5 volt power supply, one at a time, while monitoring the 5 volt supply.

4. When the shorted sensor is unplugged, the PCM will wake up and scan tool communication will return.

5. The wiring harness could also be shorted to ground on one of the 5 volt power supply wires. Cut the wires at the PCM on pins C1-17 and just unplug the center connector. Then check for the 5 volts on the PCM of the connector or checking for any continuity to ground with the sensors unplugged at the PCM connector on C1-17 and C2-31 to check the wiring harness

Don't even THINK about replacing the PCM right now. That's way down the list of possibles.The P0102 can be caused by a significant vacuum leak and that would also cause a very high idle speed. Check the air duct that runs from the MAF to the intake. Look for anything that would let in unmetered air. The P0122 is pretty easy to check. Remove the plug from the TPS and measure reference voltage (key in RUN position) on the gray wire. It should be 5V dc. If it's not, backprobe the gray wire right at the PCM at pin 16. You should see 5-volts there. If you do, then you have a wiring issue between the PCM and TPS. The reference voltage is spliced between the PCM and the TPS. The splice provides the 5v to the linear EGR vavle, MAP and fuel tank pressure sensor.

Until you check the reference voltage, you have NO basis to think that the problem is in the PCM.

The chances of the PCM being defective or slim to nearly none.

Will it give you codes on the dash if you turn the key on and off 3 times.

Code 34 is set when the computer does not detect a voltage to and through the speed control servo. The cruise control computer is built into the PCM, which grounds two windings in the servo mechanism to regulate the vacuum applied to the servo diaphragm.
Note: All Chrysler corporation fuel-injected engines have the computer circuitry and software for the cruise control system installed, even if there is no cruise control installed on the vehicle. If there is no cruise control installed on the care or truck, the computer will interpret this as an open winding and set code 34.
First: turn the key ON, turn the cruise switch ON, and look for +12 Volts on the dark blue/red wire that connects to the servo mechanism. This circuit is fed:

• from the ignition switch through to 10 (dark blue wire)
• from fuse 10 to the steering column (white/red wire)
• through the clock spring to the cruise control ON/OFF switch on the steering wheel (white/red wire)
• back through the clockspring to joint connect "C" (yellow/red wire)
• to the brake lamp switch under the dashboard (yellow/red wire)
• through the firewall from the brake switch (dark blue/red wire)
• to the servo (dark blue/red wire) A break anywhere in this path (broken wire, bad brake switch, loose connector, etc.) will interrupt the 12 volt supply to the servo and set a fault code. Work backwards until you locate the break.
  

Turn the key OFF. Unplug the the connector from the servo and measure the servo coil resistances.

• measure the resistance between the servo pin that connects to the tan/red wire and the servo pin that connects to the dark blue/red wire.
• measure the resistance between the servo pin that connects to the light green/red wire and the servo pin that connects to the dark blue/red wire. The resistance in both cases should be above 0 ohms and less than infinity.
  

Disconnect the battery(s). Unplug the 60 pin connector from the PCM and check for continuity between the pcm connector and the servo connector for the tan/red wire (cavity 33) and the light green/red wire (cavity 53).
If no wiring problems are found, check the PCM connectors for corrosion, and reconnect. Reconnect the battery and test the circuit again. If the problem still exists, the PCM is probably bad. NOTE: Personally, if the truck was out of warranty I would try to find for a used servo before buying a new PCM.

Please rate me solved...thanks!
DTC P1259: VTEC SYSTEM MALFUNCTION
1. Perform PCM reset procedure. See SELF-DIAGNOSTICS - INTRODUCTION article. Start engine
and run at 3000 RPM with no loads and transmission in Park or Neutral until radiator fan comes on. Road
test vehicle. Accelerate in 1st gear to an engine speed over 4000 RPM and hold that engine speed for at
least 2 seconds. If DTC P1259 is not indicated during first road test, repeat road test 2 more times. If DTC
P1259 is indicated, go to next step. If DTC P1259 is not indicated, problem is intermittent. System is
okay at this time. Check for poor connections or loose wires at VTEC solenoid valve connector and PCM.
See ENGINE PERFORMANCE WIRING DIAGRAMS article. Repair as necessary.
2. Turn ignition off. Disconnect VTEC pressure switch 2-pin connector. Check for continuity between
VTEC pressure switch terminals. If continuity exists, go to next step. If continuity does not exist, replace
VTEC pressure switch.
3. Turn ignition on. Measure voltage between ground and VTEC pressure switch harness connector terminal
No. 2 (Blue/Black wire). If about 12 volts exist, go to next step. If about 12 volts do not exist, check for
an open or short in Blue/Black wire between VTEC pressure switch and PCM 31-pin connector "C"
terminal No. 10. Repair as necessary. If wire is okay, substitute a known-good PCM and recheck. See
SUBSTITUTING PCM in SELF-DIAGNOSTICS - INTRODUCTION article. If symptom or problem
goes away, replace original PCM.
4. Measure voltage between VTEC pressure switch harness connector terminals. If battery voltage exists, go
to next step. If battery voltage does not exist, repair open in Brown/Black wire between VTEC pressure
switch and ground connector located on left side of engine, under throttle plate, between end of radiator
hose and cooling fan switch. See ENGINE PERFORMANCE WIRING DIAGRAMS article. If wire is
okay , substitute a known-good PCM and recheck. See SUBSTITUTING PCM in SELFDIAGNOSTICS
- INTRODUCTION article. If symptom or problem goes away, replace original PCM.
5. Turn ignition off. Disconnect VTEC solenoid valve connector. Measure resistance between ground and
VTEC solenoid valve connector. See ENGINE PERFORMANCE WIRING DIAGRAMS article. If
resistance is 14-30 ohms, go to next step. If resistance is not 14-30 ohms, replace VTEC solenoid valve.
6. Remove VTEC pressure switch and install Pressure Gauge Adaptor (07NAJ-P07010A) and A/T Low
Pressure Gauge (07406-0070300). Reinstall VTEC pressure switch into adaptor. Connect tachometer.
Start engine and with no loads and transmission in Park or Neutral until radiator fan comes on. Because
engine is running with no load, oil pressure must be checked within one minute. Check oil pressure at
engine speeds of 1000, 2000 and 3000 RPM. If oil pressure is less than 7 psi (48 kPa), go to next step. If
oil pressure is 7 psi (48 kPa) or more, check VTEC solenoid valve. See SYSTEM & COMPONENT
TESTING article.
7. Turn ignition off. Disconnect VTEC solenoid valve connector. Connect a fused jumper wire between
battery voltage and VTEC solenoid valve connector. Start engine and check oil pressure at 3000 RPM. If
oil pressure is more than 57 psi (393 kPa), go to next step. If oil pressure is 57 psi (393 kPa) or less,
check VTEC solenoid valve. See SYSTEM & COMPONENT TESTING article.
8. Ensure jumper wire is still connected to VTEC solenoid valve connector. Start engine and allow it to idle.
Set engine speed to more than 4000 RPM and measure voltage between ground and PCM 31-pin
connector "C" terminal No. 10 (Blue/Black wire). See ENGINE PERFORMANCE WIRING
DIAGRAMS article. If battery voltage exists, go to next step. If battery voltage does not exist, replace
VTEC pressure switch.
9. Turn ignition off and disconnect jumper wire. Check for continuity between VTEC solenoid valve
harness connector and PCM 25-pin connector "B" terminal No. 12 (Green/Yellow wire). See Fig. 2 . See
ENGINE PERFORMANCE WIRING DIAGRAMS article. If continuity exists, go to next step. If
continuity does not exist, repair open in Green/Yellow wire between VTEC solenoid valve connector and
PCM 25-pin connector "B" terminal No. 12.
10. Check for continuity between ground and VTEC solenoid valve connector. See ENGINE
PERFORMANCE WIRING DIAGRAMS article. If continuity exists, repair short in Green/Yellow
wire between VTEC solenoid valve connector and PCM 25-pin connector "B" terminal No. 12. If
continuity does not exist, substitute a known-good PCM and recheck. See SUBSTITUTING PCM in
SELF-DIAGNOSTICS - INTRODUCTION article. If symptom or problem goes away, replace original
PCM