Allison 1000 & 2000 Gen 4 Fault Codes: P0841 Transmission Pressure Switch Solenoid C Circuit Stuck Open CIRCUIT DESCRIPTION:The Pressure Switch Manifold (PSM) is a multiple-switch assembly made up of three normally open (N/O) and one normally closed (N/C) pressure switches. The C pressure switch monitors C shift valve positioning and relays it to the TCM. When C pressure switch is in the open state, C shift valve should be in the destroked position. CONDITIONS FOR RUNNING THE DTC:1. The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater than 18V...

Allison 1000 & 2000 Gen 4 Fault Codes: P0842 Transmission Pressure Switch Solenoid C Circuit Stuck Closed CIRCUIT DESCRIPTION:The Pressure Switch Manifold (PSM) is a multiple-switch assembly made up of three normally open (N/O) and one normally closed (N/C) pressure switches. The C pressure switch monitors C shift valve positioning and relays it to the TCM. When C pressure switch is in the open state, C shift valve should be in the destroked position. CONDITIONS FOR RUNNING THE DTC:1. The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater than 18V...

Allison 1000 & 2000 Gen 4 Fault Codes: P0843 Transmission Pressure Switch Solenoid C Circuit High CIRCUIT DESCRIPTION:The Pressure Switch Manifold (PSM) is a multiple-switch assembly made up of three normally open (N/O) and one normally closed (N/C) pressure switches. The C pressure switch monitors C shift valve positioning and relays it to the TCM. When C pressure switch is in the open state, C shift valve should be in the destroked position. CONDITIONS FOR RUNNING THE DTC:1. Components are powered and the ignition voltage is greater than 5V.2. DTC P0561, P0562, or P0563 is not active.3. C shift valve...

Allison 1000 & 2000 Gen 4 Fault Codes: P0845 Transmission Pressure Switch Solenoid D Circuit CIRCUIT DESCRIPTION:The Pressure Switch Manifold (PSM) is a multiple-switch assembly made up of three normally open (N/O) and one normally closed (N/C) pressure switches. The D pressure switch monitors D shift valve positioning and relays it to the TCM. When D pressure switch is in the open state, D shift valve should be in the destroked position. CONDITIONS FOR RUNNING THE DTC:1. Components are powered and the ignition voltage is greater than 5V.2. DTC P0561, P0562, or P0563 is not active.3. D shift valve is...

Allison 1000 & 2000 Gen 4 Fault Codes: P0846 Transmission Pressure Switch Solenoid D Circuit Stuck Open CIRCUIT DESCRIPTION:The Pressure Switch Manifold (PSM) is a multiple-switch assembly made up of three normally open (N/O) and one normally closed (N/C) pressure switches. The D pressure switch monitors D shift valve positioning and relays it to the TCM. When D pressure switch is in the open state, D shift valve should be in the destroked position. CONDITIONS FOR RUNNING THE DTC:1. The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater than 18V...