Ascender 4WD L6-4.2L (2003)
Torque Converter: Technical Service Bulletins
A/T - DTC P0894/P1870 Diagnostic Information
Information IB08-05-S003
Issue Date: FEBRUARY 2008
Diagnostic Information On Diagnostic Trouble Code (DTC) P0894 And P1870
Affected Vehicles
2003-2007 Isuzu Ascender
2007 Isuzu i-290/i-370 (TI) with Automatic Transmission
2006 Isuzu i-280/i-350 (TI) with Automatic Transmission
Service Information
Diagnostic trouble codes (DTC) P0894 and P1870, Transmission Component Slipping, may have different root causes. The following diagnostic tips are
provided to assist in accurately repairing the condition.
^
Bulletin Number SB08-04-S001 is intended for 2006 vehicles only. This bulletin provides diagnostic procedures to determine if the TCC enable
solenoid is cracked.
^
Slip speeds ranging from approximately 100 to 400 RPM at steady state light load driving are usually caused by the TCC not applying.
^
Slip speeds greater than about 400 RPM at steady state driving are usually caused by a slipping clutch or band. Inspect the oil pan for the presence of
excess clutch debris.
^
A plugged or restricted TCC apply fluid orifice (238, located in the pump) may cause DTC P0894 or P1870, especially in low mileage vehicles with
less than 8,000 km (5,000 mi).
^
A converter clutch valve (224, located in the pump), which does not have full travel of 13 mm (0.5 in) or is stuck in the off position may cause DTC
P0894 or P1870.
^
Inspect the valve for chips, debris, nicks or burrs. Also, inspect the springs (225 and 226) to make sure they are not limiting valve travel. A spring
that is not fully wound may catch in the bore, limit valve travel and cause DTC P0894 or P1870.
^
A cracked or leaking TCC solenoid (part of harness 66) may cause DTC P0894 or P1870. Use solenoid test kit J 44246 to test the operation of this
solenoid.
^
A cracked or leaking TCC PWM solenoid (396) may also cause DTC P0894 or P1870.
^
If the vehicle has 24,000 miles (38,600 km) or more, and diagnostics have not determined another cause of the DTC, the torque converter should be
replaced.
When attempting to diagnose a DTC P0894 or P1870, it is important to also refer to the appropriate Service Information (SI) document for further
possible causes of this condition.
Disclaimer