Toyota Celica 2005 Repair Manual page 936

DTC P0793
CIRCUIT DESCRIPTION
This sensor detects the rotation speed of the counter gear. By comparing the counter gear speed signal (NC)
with the input turbine speed sensor signal (NT), the ECM detects the shift timing of the gears and appropri-
ately controls the engine torque and hydraulic pressure in response to various conditions, thus performing
smooth gear shifting.
DTC No.
All conditions below are detected for 5 secs. or more
(1−trip detection logic)
(a) Gear change not being performed
(b) Counter gear rpm: Less than 300 rpm
P0793
(c) T/M output shaft rpm: 1,000 rpm or more
(d) Park/neutral position switch: OFF
(e) Shift solenoid valves, park/neutral position switch and ve-
hicle speed sensor are in normal operation
MONITOR DESCRIPTION
The NC terminal of ECM detects the revolving signal from speed sensor (NC) (output rpm). The ECM outputs
a gearshift signal comparing the speed sensor (NT) with the speed sensor (NC).
While the vehicle is operating in the 2nd, 3rd or O/D gear position in the shift position of D, if the counter gear
revolution is less than 300 rpm
detects the trouble, illuminates the MIL and stores the DTC.
When the ECM detects this malfunction, the ECM performs the fail−safe function and outputs a gearshift
signal based on the signal from the speed sensor (NT).
*1: Pulse is not output or is irregularly output.
*2: The vehicle speed is 50 km/h (31 mph) or more.
MONITOR STRATEGY
Related DTCs
Required sensors/Components
Frequency of operation
Duration
MIL operation
Sequence of operation
TYPICAL ENABLING CONDITION
Item
The monitor will run whenever this DTC is
not present.
Engine
NSW switch
Output shaft rpm
2005 CELICA (RM1131U)
DIAGNOSTICS
Intermediate Shaft Speed Sensor "A"
DTC Detecting Condition
*1
although the output shaft revolution is more than 1,000 rpm
P0793
Speed sensor (NC), Speed sensor (NT), Park/neutral position switch
Continuous
5 sec.
Immediate
None
Minimum
1,000 rpm or more
− AUTOMATIC TRANSAXLE (U240E)
S Open or short in speed sensor (NC) circuit
S Speed sensor (NC)
S ECM
Direct clutch speed sensor/Verify pulse input
Specification
See page DI−669
Running
OFF
935
Trouble Area
*2
, the ECM
Maximum
−
DI−735
DIC6F−02