DIAGNOSTIC RESPONSE:Use default sump temperature CIRCUIT DESCRIPTION:The Transmission Fluid Temperature (TFT) sensor is incorporated into the internal wiring harness. The TFT sensor is thermistor (thermally sensitive resistor) that changes its resistance value based on the temperature of the transmission fluid. The Transmission Control Module (TCM) supplies a 5V reference voltage signal to a reference resistor inside the TCM that is in series with the TCT sensor. The voltage drop across the TCT sensor is constantly changing as the TFT sensor resistance varies due to the change in transmission fluid. When the transmission is cold, the sensor resistance is high and...

DIAGNOSTIC RESPONSE:DNS, Lock in current range CIRCUIT DESCRIPTION:The speed sensors are variable reluctance devices which convert mechanical motion to an AC voltage. Each sensor consists of a wire coil wrapped around a pole piece that is adjacent to a permanent magnet. These elements are contained in a housing which is mounted adjacent to rotating ferrous member. Two signal wires extend from one end of the housing and an exposed end of the pole piece is located at the opposite end of the housing. The permanent magnet produces lines of flux around the pole piece. As a ferrous object (a rib...

DIAGNOSTIC RESPONSE:DNS, Lock in current range CIRCUIT DESCRIPTION:The speed sensors are variable reluctance devices which convert mechanical motion to an AC voltage. Each sensor consists of a wire coil wrapped around a pole piece that is adjacent to a permanent magnet. These elements are contained in a housing which is mounted adjacent to rotating ferrous member. Two signal wires extend from one end of the housing and an exposed end of the pole piece is located at the opposite end of the housing. The permanent magnet produces lines of flux around the pole piece. As a ferrous object (a rib...

DIAGNOSTIC RESPONSE:Inhibit RELS operation CIRCUIT DESCRIPTION:When Function AS: Reduced Engine Load at a Stop (RELS) is active, the Transmission Control Module (TCM) automatically commands transmission operation at a reduced load state similar to Neutral (N). The purpose of the function is to reduce the load on the engine when the vehicle is stopped which improves fuel economy and reduces heat load of the transmission in high start/stop duty cycles. To active RELS, the vehicle must be in first range, at a stop, service brakes applied, accelerator pedal approximately at 0%, and the TCM GPI terminal for RELS must see V+,...

DIAGNOSTIC RESPONSE:None CIRCUIT DESCRIPTION:Some emergency vehicles are equipped with an input function known as Auxiliary Function Range Inhibit (AFRI) (Special), which prevents inadvertent range selection when auxiliary equipment is operating. This function is enabled under the following conditions:1. Input wire 101 is connected to signal return wire 103 and,2. Input wire 142 is connected to battery ground. In a typical installation, a dash-mounted auxiliary equipment selector switch completes the circuit between wires 101 and 103. A second switch closes during operation of the auxiliary equipment to complete the circuit between wire 142 and battery ground. Both switches must be closed...