P0406

C : Diagnostic Trouble Code (DTC) P0406 Indicates Exhaust Gas Recirculation (EGR) Valve Malfunction, Short to Ground/Open Circuit

C1 : CHECK FOR A SHORT TO GROUND
1. Disconnect the EGR valve electrical connectors PI 15.
2. Disconnect the powertrain control module (PCM) electrical connectors PI 1.
3. Measure the resistance between the EGR valve electrical connector PI 15 pin 4 (YU) and GROUND.

Is the resistance less than 10,000 ohms?

Yes
REPAIR the circuit between EGR valve electrical connector PI 15 pin 4 (YU) and PCM electrical connector PI 1 pin 57 (YU). CLEAR DTC. To validate fix drive vehicle between 30 mph (48 kph) and 40 mph (64 kph). Allow vehicle to idle for 2 minutes.

No
Goto C2

C2 : CHECK FOR AN OPEN CIRCUIT
1. Measure the resistance between the EGR valve electrical connector PI 15 pin 4 (YU) and PCM electrical connector PI 1 pin 57 (YU).

Is the resistance more than 5.0 ohms?

Yes
REPAIR the circuit between EGR valve electrical connector PI 15 pin 4 (YU) and PCM electrical connector PI 1 pin 57 (YU). CLEAR DTC. To validate fix drive vehicle between 30 mph (48 kph) and 40 mph (64 kph). Allow vehicle to idle for 2 minutes.

No
Goto C3

C3 : CHECK FOR A SHORT TO GROUND
1. Measure the resistance between the EGR valve electrical connector PI 15 pin 1 (YG) and GROUND.

Is the resistance less than 10,000 ohms?

Yes
REPAIR the circuit between EGR valve electrical connector PI 15 pin 1 (YG) and PCM electrical connector PI 1 pin 58 (YG). CLEAR DTC. To validate fix drive vehicle between 30 mph (48 kph) and 40 mph (64 kph). Allow vehicle to idle for 2 minutes.

No
Goto C4

C4 : CHECK FOR AN OPEN CIRCUIT
1. Measure the resistance between the EGR valve electrical connector PI 15 pin 1 (YG) and PCM electrical connector PI 1 pin 58 (YG).

Is the resistance more than 5.0 Ohms?

Yes
REPAIR the circuit between EGR valve electrical connector PI 15 pin 1 (YG) and PCM electrical connector PI 1 pin 58 (YG). CLEAR DTC. To validate fix drive vehicle between 30 mph (48 kph) and 40 mph (64 kph). Allow vehicle to idle for 2 minutes.

No
Goto C5

C5 : CHECK FOR A SHORT TO GROUND
1. Measure the resistance between the EGR valve electrical connector PI 15 pin 6 (YR) and GROUND.

Is the resistance less than 10,000 ohms?

Yes
REPAIR the circuit between EGR valve electrical connector PI 15 pin 6 (YR) and PCM electrical connector PI 1 pin 59 (YR). CLEAR DTC. TEST the system for normal operation.

No
Goto C6

C6 : CHECK FOR AN OPEN CIRCUIT
1. Measure the resistance between the EGR valve electrical connector PI 15 pin 6 (YR) and PCM electrical connector PI 1 pin 59 (YR).

Is the resistance more than 5.0 Ohms?

Yes
REPAIR the circuit between EGR valve electrical connector PI 15 pin 6 (YR) and PCM electrical connector PI 1 pin 59 (YR). CLEAR DTC. TEST the system for normal operation.

No
Goto C7

C7 : CHECK FOR A SHORT TO GROUND
1. Measure the resistance between the EGR valve electrical connector PI 15 pin 3 (YU) and GROUND.

Is the resistance less than 10,000 ohms?

Yes
REPAIR the circuit between EGR valve electrical connector PI 15 pin 3 (YU) and PCM electrical connector PI 1 pin 60 (YU). CLEAR DTC. TEST the system for normal operation.

No
Goto C8

C8 : CHECK FOR AN OPEN CIRCUIT
1. Measure the resistance between the EGR valve electrical connector PI 15 pin 3 (YU) and PCM electrical connector PI 1 pin 60 (YU).

Is the resistance more than 5.0 Ohms?

Yes
REPAIR the circuit between EGR valve electrical connector PI 15 pin 3 (YU) and PCM electrical connector PI 1 pin 60 (YU). CLEAR DTC. TEST the system for normal operation.

No
INSTALL a new EGR valve. CLEAR DTC. TEST the system for normal operation. If DTC is repeated INSTALL a new PCM. CLEAR DTC. TEST the system for normal operation.