October 30: LEMON manuals on a temporary server, it is slow and having issues, download the manuals you need! Later in November we will switch back to the fast server.

Diagnostic Aids

Code will set if PCM detects one of 2 illegal combinations. Check all connections for good contact.

Fig 1: Code 28 Schematic (Corvette) Transmission Range Pressure Switch

Fig 2: Code 28 Flow Chart (Corvette) Transmission Range Pressure Switch