P0418 Secondary Air Injection System Relay A Circuit Malfunction 2

• OBD2 Code: P0418
• Description: Secondary Air Injection System Relay A Circuit Malfunction
• Definition: This code indicates that there is a problem with the relay circuit for the secondary air injection system, which is responsible for reducing emissions by injecting fresh air into the exhaust stream.

p0418 – Secondary Air Injection System Relay A Circuit Malfunction 2

Typical Severity: Moderate

Common Causes

P0418 – Secondary Air Injection System Relay A Circuit Malfunction

• Common causes:
  • Faulty secondary air injection pump relay
  • Open or short circuit in the wiring of the secondary air injection system relay
  • Corroded or poor electrical connections related to the relay circuit
  • Defective secondary air injection pump
  • Issues with the powertrain control module (PCM)

Common Misdiagnosis

OBD2 Code: P0418

Description: Secondary Air Injection System Relay A Circuit Malfunction 2

Common Misdiagnosis: Replacing the secondary air injection pump without checking the relay or wiring for faults.

Common Diagnostic Steps

OBD2 Code: P0418

Description: Secondary Air Injection System Relay A Circuit Malfunction 2

• Check the secondary air injection relay for proper operation.
• Inspect the wiring and connectors associated with the secondary air injection system for damage or corrosion.
• Test the voltage and ground at the relay to ensure they are within specifications.
• Examine the fuse related to the secondary air injection system and replace if necessary.
• Use a scan tool to monitor live data from the secondary air injection system to identify any irregularities.
• If applicable, test the air pump for functionality and check for blockages in hoses or valves.
• Clear codes and perform a road test to see if the code returns after repairs are made.