O2 Sensor Circuit

Diagnostic conditions 

• Exhaust temperature between 250°C and 750°C
• Battery voltage between 10 V and 16 V
• Time elapsed after engine start-up greater than 200 seconds
• No secondary air
• No diagnosis of secondary air system
• No fuel tank ventilation
• No diagnosis of fuel tank ventilation system
• No other oxygen sensor faults

Possible cause of fault 

• Short circuit to ground in signal wire
• Intercore short circuit

Affected terminals 

DME control module connector II, pin 8 and oxygen sensor jack, bank 1, pin 3

DME control module connector II, pin 14 and oxygen sensor jack, bank 1, pin 4

Diagnosis/troubleshooting 

Fig 1: P0156 Work Instruction (O2 Sensor Circuit)

Courtesy of PORSCHE OF NORTH AMERICA, INC.