Note On Intermittents

If PCM Code E13 is a hard code, start engine, and enter diagnostics. Operate engine at fast idle until AUTO "closed loop" status light is turned on. Observe parameter while manipulating circuits No. 412 and 413. If PCM parameter P.1.4 stops fluctuating and stays fixed at approximately .45 volt, repair intermittent open circuit.

Check circuit No. 413 (ground to engine) for proper installation (clean, tight and star washer installed). Ground for circuit No. 413 is attached to rear of right cylinder head.

Fig 1: PCM Code E13, Schematic, Oxygen (O2) Sensor Not Ready

Courtesy of GENERAL MOTORS CORP.

Fig 2: PCM Code E13, Flow Chart, Oxygen (O2) Sensor Not Ready

Courtesy of GENERAL MOTORS CORP.

Fig 3: PCM Code E13