Diagnostic Aids

Check shifter for normal freedom of movement. The gear select indicator (PRNDL) in the IPC will flash on and off if an invalid or suspect gear position is received by the PCM. This will normally occur if the gear selector is not fully in a gear position. When a valid gear position is attained, the gear select display will immediately display the correct position. If the PRNDL on the IPC is flashing, this may be an indication that the shift cable and/or the transaxle range switch is out of adjustment.

On the scan tool, when checking the modes (circuits), OFF indicates that the circuit is low (switched/shorted to ground) and ON indicates that the circuit is high (open). The snapshot data provides valuable information in diagnosing an intermittent DTC P1520. If all digits of the transaxle range input are on, then check for an intermittent loss of ground to transaxle range switch. If an intermittent DTC P1520 occurs when the transaxle shift lever is moved, DTC is most likely caused by a misadjustment of the shift linkage or range switch, causing range switch to end up in the position between gears.

If DTC sets and PRNDL in the IPC is flashing while driving or when drive gear selector is not being moved, record the transaxle lever position and compare the values from the chart. See Fig 1. This will determine if circuit is open, shorted or intermittent.