Mechanics

96 NORTHSTAR WON'T SHIFT OUT OF 1ST GEAR,SPEEDO STILLWORKS, CODE PO741

1996 Cadillac Deville • 175,000 miles

Bought this nice running northstar with tranny 4t80e THAT WILL NOT SHIFT OUT OF 1ST gear, fluid looks good and clear, I added 1 pint tranny fix, have driven 40 miles in 1st gear, turns 3350 rpm at 50 mph, have tried to manually shift, speedo still worksproperly. Display says to service transmission, check oil level( even after I changed engine oil and filter.) Only 2 codes appear. PO420 Catalyst. And PO741, say's torque converter clutch solonoid. Or stuck off
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Deville Dad
January 15, 2012.




Have the exhaust system checked out and test the TCC solenoid

Tiny
Rasmataz
Jan 15, 2012.
How do I test the TCC solenoid, where is it located, and how easy is it to replace?
Would the other code be a bad catalytic converter and how do you tell if those are bad?

Tiny
Deville Dad
Jan 16, 2012.
The TCC solenoid is within the tranny valve body- P0420 could be a Cat or Oxygen sensor problem-Get a 5 gas analysis

Tiny
Rasmataz
Jan 16, 2012.
Soleniods in that 1 are on bottom drop pan to access. Test em all.

Tiny
Fixitmr
Jan 16, 2012.
Can you get to it by taking off the transmission pan? How do you test it?
AD

Tiny
Deville Dad
Jan 16, 2012.
P0741, TCC STUCK OFF
Circuit Description

Torque Converter Clutch (TCC) Pulse Width Modulated (PWM) solenoid controls fluid for TCC apply and release. PCM commands solenoid on and off through ground circuit. When TCC PWM solenoid is de-energized, solenoid will release fluid and release TCC. DTC P0741 detects a high torque converter slip when TCC is commanded on.

Conditions For Setting DTC P0741

DTC will set under the following conditions: a) DTC P0101, P0102 or P0103 (MAF sensor) is not present.
B) DTC P0121, P0122 or P0123 (throttle position sensor) is not present.
C) DTC P0502 or P0503 (vehicle speed sensor) is not present.
D) DTC P0716 or P0717 (input speed sensor) is not present.
E) DTC P0742 (TCC stuck on) is not present.
F) DTC P1810 (TFP position switch) is not present.
G) DTC P1860 (TCC PWM solenoid) is not present.
H) Throttle angle is more than 8 degrees.
I) Engine must be running for at least 5 seconds.
J) Gear ratio must indicate 2nd, 3rd or 4th gear.
K) TFP position switch must is not in Park or Neutral.
L) Fluid temperature must be 68-248 F (20-120 C).
M) TCC slip speed does not exceed torque limits.
N) Delivered torque is 32-150 ft. Lbs. (43-202 N.M).
O) Not in fuel shut off mode.
P) TCC solenoid valve is commanded on at maximum duty cycle.

DTC P0741 will be stored in PCM history. MIL will light at first failure signal. SERVICE ENGINE SOON, SERVICE TRANSMISSION displays on Drivers Information Center (DIC). PCM inhibits TCC engagement and 4th gear.

Diagnostic Procedures

NOTE: Perform OBD system check prior to performing diagnostic procedures.

1. Ensure transaxle fluid level is correct. 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. Repair DTC P0719 first.

2. Drive vehicle at 45 MPH. Select "Output Test". Select "TCC Ena Sol.". Command TCC enable solenoid on. Monitor TCC slip. If TCC slip is -10 -67 RPM, see DIAGNOSTIC AIDS. If TCC slip is not -10 -67 RPM, check and repair following then go to next step.

A) TCC control valve, regulator valve or feed valve are stuck off.
B) Oil pressure screen plugged.
C) TCC solenoid "O" ring is leaking or cut.
D) Turbine shaft seals are cut or worn.
E) TCC for ballooning.

3. After repair is complete, select DTC on scan tool. Select "Clear Info" function. Drive vehicle in D4. Ensure TCC applies for more than 5 seconds. Select "Specific DTC" and enter DTC "P0741". If DTC P0741 is not present, repair is complete. If DTC P0741 is still present, repeat test.

Diagnostic Aids

Ensure transaxle fluid level is correct. Transaxle may be in hot mode. Inspect transaxle cooler lines for being pinched, plugged or twisted.

Inspect wiring for poor connections at PCM and at transmission 20-pin connector. 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.

KHLow2008
Jan 20, 2012.

AD