Description of On-Board Diagnostics

Data acquired from sensors during the stationary and road tests can be monitored with the DRBII through the State Displays. State Display parameters include:

TCU ID -- A two digit number exclusively assigned to the vehicle in which the transmission is installed.

TPS Position -- A bar graph with 1-7 segments corresponding to Throttle Position Switch position (and throttle plate angles). A functioning and correctly adjusted TPS should yield all numbers when exercised through its complete range.

RPM -- Output shaft revolutions per minute

Mode Switch ("C" or "P") -- Indicates comfort or power mode selector for optimum fuel/performance characteristics.

Brake Switch -- ON or OFF relative to the state of the brake switch.

Gear Selector Status -- PRND is displayed it the selector is in Park, Reverse, Neutral, or Drive. 1-2 is displayed it the selector is in the lowest position, and a 3 is displayed if the selector is in the intermediate position.

Solenoid Status -- Shown as S1 +/- S2 +/- S3 +/- indicating whether a solenoid is ON (+) or OFF (-).

Gear -- Monitors what gear the transmission is currently in (1st through 4th).

Status xx yy -- A non-zero value in xx indicates a solenoid fault. A non-zero value in yy indicates a TPS fault. In both cases, the functional test should be run to determine the definition of the fault. If there are any non-zero values in the status, and there are no faults reported through the functional test, an intermittent fault may be suspected.

NOTE: A current fault will appear in both the current fault status and the stored fault status. If a stored solenoid fault is present with NO current fault, an intermittent fault can be assumed and fault isolation should proceed according to the diagnostic fault trees. To erase a stored fault, the TCU should be disconnected from the harness for at least 15 seconds. Do not disconnect the battery as this will destroy data stored in other vehicle system control computers.