Note On Intermittents

PCM Code E34 is usually set by a vacuum supply problem to MAP sensor. Check for improper vacuum hose routing, MAP hose connected to improper throttle body port, and chafed, pinched or cut MAP hose. Apply vacuum to MAP hose at throttle body, and look for vacuum leaks in MAP hose and MAP sensor. Manipulate affected wiring and connections while observing PCM parameter P.0.2 for jump or skip with vacuum applied. If data display jumps high, condition has been induced and cause of intermittent can be repaired. If no faults are found, substitute a known good MAP sensor, and retest.

Fig 1: PCM Code E34, Schematic, MAP Signal Too High

Courtesy of GENERAL MOTORS CORP.

Fig 2: PCM Code E34, Flow Chart, MAP Signal Too High

Courtesy of GENERAL MOTORS CORP.

Fig 3: PCM Code E34