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Unread 07-16-2013, 10:34 AM   #1
speedyo
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P0756 and p0758 help

It started with p0758 Soldenoid b electrical. So i changed the TPS to eliminate the possibility of it. I then ordered all 3 solenoids and changed them. Well the check engine light went off and drove it today. It went well for 50 miles and i was pumped thinking it was fixed. Then all of a sudden CEL and when i hit about 35-40 mph it slips and wont shift into 4th gear. The new codes are P0758 and P0756.

P0756 is solenoid 2 stuck open/closed malfunction. What could this possibly be thanks so much!

I have tried adjusting TC, Fluid is right level, electrical connections look fine.

Update this morning i drove it and now i have lost 1st gear and 2nd. I put in drive and im in 3rd gear and it wont downshift or upshift at all. Any help or advice would be greatly appreciated!

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Unread 07-16-2013, 10:39 AM   #2
speedyo
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99 jeep cherokee 4.0 btw
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Unread 07-16-2013, 12:28 PM   #3
JeepCares
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Excerpts from the 1999 XJ FSM:

Symptom:
P0756 SOLENOID B FUNCTIONAL FAULT
When Monitored and Set Condition:
P0756 SOLENOID B FUNCTIONAL FAULT
When Monitored: Continously while at higher vehicle speeds and high engine load
conditions. The vehicle must be driven on the road. This code will not set on a hoist.
Set Condition: The gear ratio is incorrect for the current request.
POSSIBLE CAUSES
OIL BURNT OR CONTAINS EXCESS DEBRIS
PCM DTC’S ALSO PRESENT
CODE P1747 OR P1746 ALSO PRESENT
INTERNAL TRANSMISSION PROBLEM CAUSES CODE P0756

3.3 DIAGNOSTIC TROUBLE CODES
(DTC’S)
Always begin diagnosis by performing a visual
inspection,
– check the fluid level and condition and correct
as necessary
– check and adjust manual linkage as necessary
– check the electrical connections at the PCM,
TCM, TPS, TRS and Transmission solenoid for
pushed out or corroded terminals. Make sure
all connectors are seated properly.


3.3.5 LIST OF DIAGNOSTIC TROUBLE
CODES
The TCM may report any of the following DTC’s.
Scan Name of Code
P0122 THROTTLE POSITION SENSOR SIGNAL
CIRCUIT
P0562 TRANSMISSION VOLTAGE LOW
P0563 TRANSMISSION VOLTAGE HIGH
P0705 CHECK SHIFTER SIGNAL (RANGE
SENSOR)
P0715 INPUT SPEED SENSOR
P0720 OUTPUT SPEED SENSOR
P0740 (TCC) SOLENOID C FUNCTIONAL
FAULT
P0751 SOLENOID A FUNCTIONAL FAULT
P0756 SOLENOID B FUNCTIONAL FAULT
P1694 NO CCD MESSAGE FROM PCM
P1718 INTERNAL TCM
P1742 INTERNAL TCM
P1743 INTERNAL TCM
P1744 SOLENOID A SHORTED TO GROUND
P1745 SOLENOID A SHORTED TO VOLTAGE
OR OPEN
P1746 SOLENOID B SHORTED TO GROUND
P1747 SOLENOID B SHORTED TO VOLTAGE
OR OPEN
P1748 (TCC) SOLENOID C SHORTED TO
GROUND
P1749 (TCC) SOLENOID C SHORTED TO
VOLTAGE OR OPEN
The P-codes, P1698-” No CCD messages from
TCM” and P0700 “Transmission Fault
Present” are Powertrain Symptoms (PCM
codes) and are diagnosed under the powertrain
diagnostic symptoms group.
DTC’s for AW4 transmission controller are not
permanent and will change the moment the reason
for the code is corrected.

3.4 INPUT SPEED SENSOR
The TCM uses the Input Speed Sensor (ISS) to
detect transmission solenoid functional faults (P0751
solenoid A functional fault, P0756 solenoid B functional
fault, TCC solenoid C functional fault). The ISS
is a variable reluctance sensor. Changes in the reluctance
of a magnetic circuit caused by the passing of the
rotor lobes on the overdrive clutch drum result in the
ISS outputting an AC periodic voltage wave form. The
frequency and voltage of the wave form are proportional
to the transmission input speed.
NOTE: SINCE THE OD/CLUTCH DRUM IS
STATIONARY IN 4TH GEAR OR WHEN THE
VEHICLE IS IN GEAR, BUT NOT MOVING.
THERE WILL BE NO ISS SENSOR SIGNAL.

3.5 OUTPUT SPEED SENSOR
The Transmission Control Module (TCM) uses
the Output Speed Sensor (OSS) to determine shift
points and TCC engagement points. The OSS is a
variable reluctance sensor. Changes in the reluctance
of a magnetic circuit caused by the passing of
the rotor lobes on the output shaft result in the OSS
outputting an AC periodic voltage wave form. The
frequency and voltage of the wave form are proportional
to the transmission output shaft speed.
__________________
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Chrysler Group LLC
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Unread 07-16-2013, 12:49 PM   #4
speedyo
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So we are looking at most likely an internal problem?
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Unread 07-16-2013, 02:29 PM   #5
JeepCares
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I honestly can't tell you. I'm not a technician. Maybe someone else can jump in here.
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Unread 07-16-2013, 07:20 PM   #6
speedyo
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any input anyone need to try to resolve this asap.
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