Workshop Manual

7A1–48
TRANSMISSION CONTROL SYSTEM (4L30–E)
DTC P0723 Automatic Transmission Output Speed Sensor (OSS) Intermittent
D07R200006
Circuit Description
Output speed information is provided to the PCM by the
OSS, which is a permanent magnet (PM) generator. The
PM generator produces a pulsing AC voltage. The AC
voltage level and number of pulses increases as the
speed of the vehicle increases. The PCM then converts
the pulsing voltage to output speed, which is used for
calculations. The vehicle speed can be displayed with a
scan tool.
This DTC detects a fast decrease of output speed when
engine running in a drive gear range. This is a type “B”
DTC.
Conditions For Setting The DTC
Drive range
B Engine running time is greater than 5 seconds.
B Output speed is greater than 1300 rpm for 2 second.
B NORAW–NOLAST < 200 rpm for 2 seconds.
B NORAW: Latest raw data of output shaft speed.
B NOLAST: Fitered previous data of output speed.
B Transmission negative output speed change is
greater than 1300 rpm.
B Conditions met for 3 seconds.
Action During Detection Time
B Output speed value is frozen
Action Taken When The DTC Sets
B Fixed to 4th gear.
B Maximum line pressure.
B Inhibit TCC engagement.
B For lamp illuminate refer to DTC type definition (type
B).
Conditions For Clearing The MIL/DTC
B The PCM will turn off the MIL and CHECK TRANS
Lamp after three consecutive ignition cycles without a
failure reported.
B The DTC can be cleared from the PCM history by
using a scan tool.
B The DTC will be cleared from history when the vehicle
has achieved 40 warmup cycles without a failure
reported.
B The PCM will cancel the DTC default actions when
the fault no longer exists and the ignition is cycled “off”
long enough to power down the PCM.
Diagnostic Aids
B A OSS DTC P0723 will set when output speed has
been detected and is lost.
B Inspect the wiring for poor electrical connection at the
PCM. Look for possible bent, backed out, deformed
or damaged terminals. Check for weak terminal
tension as well. Also check for a chafed wire that
could short to bare metal or other wiring. Inspect for a
broken wire inside the insulation.
B When diagnosing for a possible intermittent short or
open condition, move the wiring harness while
observing test equipment for a change.
Test Description
The numbers below refer to the step numbers on the
diagnostic chart:
4. This test checks the OSS circuit.
5. This test checks the integrity of the OSS.
7. This test checks the 5–volt and ground circuit of the
PCM.