problem is found, measure resistance between output speed sensor
terminals. If resistance is 300-1200 ohms, go to next step. If
resistance is not as specified, replace output speed sensor.
7) Reconnect output speed sensor. Measure resistance between
ground and output speed sensor ground circuit at PCM harness
connector. If resistance is greater than 5 ohms, go to next step. If
resistance is not as specified, repair output speed sensor ground
circuit for a short to ground.
8) Measure resistance between ground and output speed sensor
signal circuit at PCM harness connector. If resistance is less than 5
ohms, repair output speed sensor signal circuit for a short to ground.
If resistance is not as specified, go to next step.
9) Measure resistance between output speed sensor signal
circuit and ground circuit at PCM harness connector. If resistance is
300-1200 ohms, replace PCM. If resistance is not as specified, go to
next step.
10) Disconnect output speed sensor harness connector. Measure
resistance of output speed sensor signal circuit between output speed
sensor harness connector and PCM harness connector. If resistance is
greater than 5 ohms, repair open in output speed sensor signal
circuit. If resistance is not as specified, repair open in output
speed sensor ground circuit.
11) Turn ignition on. Measure voltage between ground and
speed sensor ground circuit at PCM harness connector. Place gearshift
lever in each gear position and record voltage at each position. If
voltage is greater than one volt in any gear position, repair speed
sensor ground circuit for a short to power. If voltage is not as
specified, go to next step.
12) Raise and support vehicle. Start engine. Place gearshift
lever in "OD" position. Release brakes and allow wheels to rotate.
Using scan tool, monitor output speed sensor. While monitoring output
speed sensor, wiggle harness between output speed sensor and PCM. If
reading dropped towards zero while wiggling harness, repair
intermittent short or open in harness. If reading does not drop
towards zero while wiggling harness, problem is intermittent. See
INACTIVE DTC CONDITION under SELF-DIAGNOSTIC SYSTEM. Testing is
complete.
DTC P0740: TORQ CONV CLU, NO RPM DROP AT LOCKUP
Circuit Description
Circuit is monitored continuously while key is on, and gear
selector is not in Park or Neutral. Code sets if Torque Converter
Clutch (TCC) does not achieve desired drop in RPM when TCC solenoid is\
near maximum duty cycle. A bad test 3 consecutive times is required to
set code.
Possible Causes
* Misfire trouble code set.
* Vehicle stalls (faulty TCC solenoid).
* TCC shaft seal/seal defective.
* Transmission fluid contaminated.
* TCC solenoid wiring harness defective.
* TCC defective.
* TCC hydraulic circuit damaged.
Diagnostic Procedure
1) Using scan tool, read DTCs. On all bodies except AB and WJ
bodies, go to next step. On AB and WJ bodies, if DTC SPECIFIC GOOD
TRIPS counter is not displayed or displayed count is not "0", go to
step 10). If DTC SPECIFIC GOOD TRIPS counter is displayed and
displayed count is "0", indicating DTC still exists, go to next step.