Info - Diagnostic Information on DTC P1870 #02-07-30-001
Diagnostic Information on DTC P1870
2000-2002 Passenger Cars and Light Duty Trucks
with a 4L60E or 4L65E Automatic Transmission
Diagnostic trouble code (DTC) P1870, Transmission Component Slipping, may
have different root causes. The following diagnostic tips are provided to
assist in accurately repairing the condition.
Corporate Bulletin Number 01-07-30-023A, dated November 2001, is intended
for 1996-1999 vehicles with more than 32,000 km (20,000 mi). This bulletin
addresses wear in the valve body TCC isolator/regulator bore which can
cause DTC P1870. This wear condition is not the cause of DTC P1870 on any
2000 model year vehicle built after January 15, 2000, or any 2001 or 2002
vehicles as the valve body used on these vehicles has been revised to
prevent the wear condition.
Corporate Bulletin Number 99-07-30-005, dated March 1999, should be used
to help with diagnosis of this DTC. This bulletin will help to determine
if the DTC is caused by the TCC system or by a slipping internal
transmission component such as a clutch or band.
A plugged or restricted TCC apply fluid orifice (238, located in the pump)
may cause DTC 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 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 P1870.
A cracked or leaking TCC solenoid (part of harness 66) may cause DTC
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 P1870.
When attempting to diagnose a DTC P1870, it is important to also refer to
the appropriate Service Manual for further possible causes of this
condition.