P1810

WITH 4L60-E AUTOMATIC TRANSMISSION

DTC P1810 Transmission (TR) Switch Assembly Circuit Malfunction:

Transmission Range (TR) Pressure Switch Assembly Wiring Assembly:

CIRCUIT DESCRIPTION
The Transmission Range (TR) switch assembly consists of five pressure switches (two normally closed and three normally open), and a Transmission Fluid Temperature (TFT) sensor combined into one unit and mounted on the valve body. The Vehicle Control Module-A (VCM-A) supplies battery voltage to each range signal. By grounding one or more of these circuits through various combinations of the pressure switches, the VCM-A detects what manual valve position has been selected and compares the actual voltage combination of the switches to a TR combination chart stored in memory.
The TR assembly cannot distinguish between Park and Neutral because the monitored valve body pressures are identical in both cases. With ignition "ON" and engine "OFF", P/N will be indicated. When transmission electrical connector is disconnected, the ground potential for the three range signal to the VCM-A will be removed, and with ignition "ON", D2 will be indicated. DTC Type (D).

DTC P1810 WILL SET WHEN
- Range signals "A" and "C" are both zero volts "ON" for five seconds.
- Range signals "A", "B" and "C" are zero volts "ON" for five seconds.
- Range signal "C" is off:
- 4th gear.
- TCC"ON."
- Gear ratio is between 0.54 and 0.75.
- All conditions met for 24 seconds.

ACTION TAKEN (VCM-A will default to)
- No Torque Converter Clutch (TCC).
- Harsh shifts.
- Drive 4 shift pattern.
- No fourth gear in hot mode.
- Malfunction Indicator Lamp (MIL) will be on (if applicable).
- DTC P1810 will be stored in VCM-A memory.

DTC P1810 WILL CLEAR DEFAULT ACTION WHEN
The fault condition(s) no longer exist and the ignition switch is cycled from "OFF" for five seconds, then "ON".

DTC P181O WILL PASS WHEN
- The VCM-A will report a "PASS" when range signals "A" and "C" have a legal combination and vehicle is driven with TCC "ON" for 24 seconds.
- The VCM-A turns "OFF" the Malfunction Indicator Lamp (MIL) after three consecutive ignition cycles with reported passes (if applicable).
- All enable criteria are met.

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. This test checks the indicated range signal to the manual valve position actually selected.
2. This test checks for correct voltage from the VCM-A to the transmission external connector.
3. This test checks a short to ground or an open in any one of the three circuits.

Valve Combination Chart:

DIAGNOSTIC AIDS
DTC P1810 will set if the VCM-A detects one of two "Illegal" combinations.
Refer to accompanying chart for various A/B/C range combinations.
Check all wiring connectors for proper terminal tension.
Refer to Pressure Switch Assembly Resistance Check for further information. Refer to Computers and Control Systems. Testing and Inspection