LEMON Manuals: Even more car manuals for everyone
Home >> Chrysler >> 2009 >> PT Cruiser Limited >> Repair and Diagnosis >> External Pages >> Different car >> Section 59 (DTCS P0443 To P0533) >> P0491-Secondary Air Injection System Insufficient Flow >> Possible Causes

Possible Causes

WARNING: This page is about a different car, the 2009 Dodge Caliber. However, it is still accessible from the selected car via links, so may be relevant.
Possible Causes 
OBSTRUCTION OR LEAK IN THE SECONDARY AIR SYSTEM
(A929) FUSED B+ CIRCUIT OPEN OR HIGH RESISTANCE
(Z932) GROUND CIRCUIT OPEN OR HIGH RESISTANCE
(A161) FUSED B+ CIRCUIT OPEN OR HIGH RESISTANCE
(K157) MAF SENSOR SIGNAL CIRCUIT SHORT TO VOLTAGE
(K157) MAF SENSOR SIGNAL CIRCUIT SHORT TO GROUND
(K157) MAF SENSOR SIGNAL CIRCUIT OPEN OR HIGH RESISTANCE
(K957) MAF SENSOR GROUND CIRCUIT OPEN OR HIGH RESISTANCE
(F343) FUSED ASD/MAIN RELAY OUTPUT CIRCUIT OPEN OR HIGH RESISTANCE
SECONDARY AIR CHECK VALVE
SECONDARY AIR PUMP ASSEMBLY
POWERTRAIN CONTROL MODULE (PCM)

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. See  DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure  .