1996 GMC Jimmy Transmission won't shift past 2nd gear

Tiny
TAZCHARLIE
  • MEMBER
  • 1996 GMC JIMMY
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 180,000 MILES
4 months ago, car would fail to go into 3rd or 4th occasionally.
Now, car will not go above 1st or 2nd.
If I start out in Drive or Overdrive, car will stay in 1st gear.
If I start out in 2nd, car will shift from 1st to 2nd. Then, if I shift into Drive or Overdrive, the car will stay in 2nd, or will drop out of gear.

Car currently gives the following trouble codes: P0135, P0340, P0301, P0758
Car also needs a rear brake line, so the brake & antilock brake warning lights are on. (Could this put me in limp mode?)

The problem of not going above 2nd gear started about 15 miles after a new fuel pump was installed.

Transmission fluid level has been kept at proper level.
I tried resetting the computer by disconnecting the battery. No help.
My next step is to get a transmission filter and fluid change. If that doesn’t help, what am I looking at?
I know one of the codes is for a shift solenoid. Is it likely a bad solenoid, or a bad connection?

Would appreciate your help very much.
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Tuesday, September 8th, 2009 AT 10:47 AM

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Tiny
BMRFIXIT
  • EXPERT
The brake line will not cause tranny problem
the codes say it all
check fuses and wiring harness

P0758, 2-3 SHIFT SOLENOID ("B") ELECTRICAL MALFUNCTION
NOTE:Perform OBD system check prior to performing diagnostic procedures.

Circuit Description
The 2-3 shift solenoid (solenoid "B") is used to control fluid flow acting on 2-3 shift valve. Solenoid is a normally open exhaust valve that is used in conjunction with 1-2 shift solenoid (solenoid "A"), to allow 4 different shifting combinations. See the SHIFT SOLENOID COMBINATIONS table. Solenoid is attached to control valve body. Ignition voltage is supplied directly to solenoid through fused circuit. PCM commands solenoid on or off through ground circuit. DTC P0758 detects a continuous open or short to ground in 2-3 shift solenoid circuit.
Conditions For Setting DTC P0758
DTC will set under the following conditions:
Ignition is on.
System voltage is 10-17 volts.
PCM commands solenoid on and voltage remains high (battery voltage).
PCM commands solenoid off and voltage remains low (zero volts).
All conditions are met for 5 seconds.
DTC P0758 will be stored in PCM history. MIL will light at first failure signal, PCM inhibits TCC engagement, freezes shift adapts from being updated and commands maximum line pressure. Transmission operates in 3rd gear only.
SHIFT SOLENOID COMBINATIONS
Gear1-2 Shift Solenoid2-3 Shift Solenoid
1stOnOn
2ndOffOn
3rdOffOff
4thOnOff

Diagnostic Procedures
Connect scan tool to DLC. Turn ignition switch to ON position. DO NOT start engine. Using scan tool, record freeze frame and failure records for reference. Data will be lost when DTCs are cleared later in this test.
If DTCs P0753, P1860, P1864 and P1886 are not present, go to next step. If DTCs P0753, P0758, P1860, P1864 and P1886 are present, remove appropriate 2-3 shift solenoid ignition feed circuit fuse from underhood electrical center and inspect fuse. Refer to the WIRING DIAGRAMS. Replace fuse if necessary, and check for short to ground in wiring harness between transmission 20-pin connector and fuse. Repair wiring as necessary, then go to step 12. If fuse is okay, check for open in wiring harness between transmission 20-way connector and fuse. Repair wire as necessary, then go to step 12.
Using scan tool, command 2-3 shift solenoid on and off 3 times while listening at transmission oil pan. If solenoid does not click when commanded on and off, go to next step. If solenoid clicks when commanded on and off, inspect wiring for poor connections at PCM and transmission 20-pin connector. Check for possible bent, backed out, deformed or damaged terminals. Repair as necessary, then go to step 12. If connections and terminals are okay, see DIAGNOSTIC AIDS below.
Turn ignition off. Disconnect transmission 20-pin connector. Install Jumper Harness (J-39775) to PCM side of transmission 20-pin connector. Connect test light between ground and 2-3 shift solenoid ignition feed circuit at transmission 20-pin connector. Turn ignition switch to ON position. DO NOT start engine.
If test light does not light, check for open or short to ground in ignition feed circuit of 2-3 shift solenoid. Repair as necessary, then go to step 12. If test light lights, connect test light between 2-3 shift solenoid ground circuit and ignition feed circuit at transmission 20-pin connector. Using scan tool, command 2-3 shift solenoid on and off 3 times. If test light cycles on and off, go to step 8. If test light does not cycle on and off 3 times, and test light is always on, go to next step. If test light is always off, go to step 7.
Check 2-3 shift solenoid ground circuit for short to ground. Repair circuit as necessary, then go to step 12. If circuit is okay, inspect wiring for poor connections at PCM connector. Check for possible bent, backed out, deformed or damaged terminals. Repair as necessary, then go to step 12. If connections and terminals are okay, replace PCM, then go to step 12.
Check for open in 2-3 shift solenoid ignition feed circuit or poor connection at PCM connector. Repair circuit as necessary, then go to step 12. If circuit is okay, inspect wiring for poor connections at PCM connector. Check for possible bent, backed out, deformed or damaged terminals. Repair as necessary, then go to step 12. If connections and terminals are okay, replace PCM, then go to step 12.
Turn ignition off. Disconnect jumper harness from PCM side of transmission 20-pin connector and install harness to transmission side of 20-pin connector. Connect ohmmeter between 2-3 shift solenoid ground circuit and ignition feed circuit at transmission 20-pin connector.
If resistance is 19-31 ohms, go to next step. If resistance is not 19-31 ohms, disconnect 2-3 shift solenoid connector. Measure resistance between 2-3 shift solenoid terminals. If resistance is 19-31 ohms, check for open circuit in transmission wiring harness. Repair as necessary, then go to step 12. If resistance is not 19-31 ohms, replace 2-3 shift solenoid, then go to step 12.
Turn ignition off. Connect ohmmeter between ground and 2-3 shift solenoid ground circuit, and between ground and 2-3 shift solenoid ignition feed circuit at transmission 20-pin connector. If resistance is more than 250 k/ohms, see DIAGNOSTIC AIDS below. If resistance is less than 250 k/ohms, go to next step.
Disconnect 2-3 shift solenoid connector. Measure resistance between ground and each solenoid terminal. If resistance is more than 250 k/ohms, check for short to ground in transmission wiring harness. Repair as necessary, then go to next step. If resistance is less than 250 k/ohms, replace 2-3 shift solenoid, then go to next step.
After repair is complete, select DTC on scan tool. Select "Clear Info" function. Test drive vehicle. Ensure voltage decreases to zero when2-3 shift solenoid is commanded on, and voltage increases to battery voltage when commanded off. Conditions must be met for 5 seconds. Select "Specific DTC" and enter DTC "P0758". If DTC P0758 is not present, repair is complete. If DTC P0758 is still present, repeat test.
Diagnostic Aids
Inspect wiring for poor connections at PCM. Check for possible bent, backed out, deformed or damaged terminals. Check for weak terminal tension. Check for chafed wire that could short to bare metal or other wiring. Check for broken wire inside insulation. If diagnosing for possible intermittent short or open condition, move wiring harness while observing scan tool for value change
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Tuesday, September 8th, 2009 AT 8:39 PM

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