Circuit Description

WARNING: This page is about a different car, the 2002 Infiniti QX4, 2001 Nissan Pathfinder, and 2001 Infiniti QX4. However, it is still accessible from the selected car via links, so may be relevant.

This is an OBD-II self-diagnostic item and not available in TCM self-diagnosis. This malfunction will not be detected while the O/D OFF indicator light is indicating another self-diagnosis malfunction.

This malfunction is detected when the transmission does not shift into 1st gear as instructed by the TCM. This is not caused by electrical malfunction (circuits open or shorted), but by mechanical malfunction (such as valve body control valve sticking, improper solenoid valve operation, etc.).

This diagnosis monitors actual gear position by checking the torque converter slip ratio calculated by TCM. Torque converter slip ratio is defined as revolution sensor signal, multiplied by gear ratio (determined as gear position which TCM supposes), divided by engine speed signal from ECM. If the actual gear position is higher than the position (1st) supposed by TCM, the slip ratio will be more than normal. In case the ratio exceeds the specified value, TCM judges this diagnosis malfunction. DTC will set when either shift solenoid valve "A" is stuck open or shift solenoid valve "B" is stuck open. Transmission will exhibit a 2-2-3-3 shift pattern if shift solenoid valve "A" is stuck open, and a 4-3-3-4 shift pattern if shift solenoid valve "B" is stuck open.