P1131
P1137

Lack Of HO2S1 Switches, Lean (Bank 1, Sensor 1)
Lack Of HO2S1 Switches, Lean (Bank 1, Sensor 2)
These codes usually do not indicate a problem with the O2 sensor. Rather, the O2 sensor is correcting rich due to an overly lean air/fuel ratio. Check Base Engine Idle, EGR, Fuel System and Air Induction System.

P1132
P1138

Lack Of HO2S1 Switches, Rich (Bank 1, Sensor 1)
Lack Of HO2S1 Switches, Rich (Bank 1, Sensor 2)
These codes usually do not indicate a problem with the O2 sensor. Rather, the O2 sensor is correcting lean due to an overly rich air/fuel ratio. Check Base Engine Idle, EGR, Fuel System and Air Induction System.

P1151
P1157

Lack Of HO2S1 Switches, Lean (Bank 2, Sensor 1)
Lack Of HO2S2 Switches, Lean (Bank 2, Sensor 2)
These codes usually do not indicate a problem with the O2 sensor. Rather, the O2 sensor is correcting rich due to an overly lean air/fuel ratio. Check Base Engine Idle, EGR, Fuel System and Air Induction System.

P1152
P1158

Lack Of HO2S1 Switches, Rich (Bank 2, Sensor 1)
Lack Of HO2S2 Switches, Rich (Bank 2, Sensor 2)
These codes usually do not indicate a problem with the O2 sensor. Rather, the O2 sensor is correcting lean due to an overly rich air/fuel ratio. Check Base Engine Idle, EGR, Fuel System and Air Induction System.

P1401

DPF-EGR Sensor Circuit High Voltage Detected
This code is set by a bad or damaged Differential Pressure Flow Exhaust Gas Recirculation (DPF-EGR) sensor or a fault in the sensor circuit. Use a sensor tester or voltmeter to check the DPF-EGR sensor and associated wiring for the cause of the problem.

P1405
P1406

DPF-EGR Sensor Upstream Hose Off or Plugged
DPF-EGR Sensor Downstream Hose Off or Plugged
These codes are set by the engine computer detecting a vacuum leak or vacuum hose being plugged on the Differential Pressure Flow Exhaust Gas Recirculation (DPF-EGR) sensor. The upstream and downstream hoses are located on the intake manifold. Use a vacuum pump to test the line for a blockage or leak.

P1443

EVAP Vacuum System, Purge or VMV Fault
Several conditions can cause this code to be set. A loose or broken gas cap, a damaged carbon canister, damaged or plugged fuel vapor hose, a damaged purge solenoid, Purge Flow (PF) sensor or Vapor Management Valve (VMV) are all possible causes. A multimeter or scan tool can be used to test the components.

P1506
P1507

Idle Air Control Overspeed Error
Idle Air Control Underspeed Error
A vacuum leak, a damaged IAC assembly, a stuck IAC valve or throttle valve typically sets one or both of these codes. The IAC can be checked with a scan tool, sensor tester or multimeter. A vacuum leak is one of the most common causes and can be checked with a vacuum pump.

P1537
P1538

Intake Manifold Runner Control Open (Bank 1)
Intake Manifold Runner Control Open (Bank 2)
The long and short intake manifold runners are part of the intake system. The Intake Manifold Runner Controls (IMRC) open and close a valve depending on driving conditions. Misrouted cables, a damaged IMRC housing or springs, binding or disconnected lever/shaft or seized gears can cause this code to be set.