Test Procedure

RL1 PRELIMINARY DIAGNOSIS

Are DTCs P20CB, P20CC, P20CD, P20CE, P2698, P269B, P269D, P269E or P26A0 present?

Yes	No
For DTCs P269B, P269D, P269E or P26A0, GO to RL2. For all others, GO to RL10.	RETURN to SYMPTOM CHARTS for further direction.

RL2 CHECK THE VPWR VOLTAGE TO THE FUEL VAPORIZER SYSTEM GLOW PLUG RELAY

Ignition OFF.
Fuel Vaporizer System Glow Plug Relay connector disconnected.
Ignition ON, engine OFF.

Measure the voltage between:

(+) Fuel Vaporizer System Glow Plug Relay Connector, Harness Side	(-)
VPWR - Pin 1, 3	Ground

Is the voltage greater than 10.5 V?

Yes	No
GO to RL3.	REPAIR the open circuit. Clear the PCM DTCs. REPEAT the self-test.

RL3 CHECK THE FUEL VAPORIZER SYSTEM GLOW PLUG RELAY

Carry out the fuel vaporizer system glow plug relay component test. Refer to the OEM WIRING DIAGRAMS COMPONENT TESTING article.

Is a concern present?

Yes	No
INSTALL a new Fuel Vaporizer System Glow Plug relay. Clear the PCM DTCs. REPEAT the self-test.	GO to RL4.

RL4 CHECK THE VGPRC CIRCUIT FOR AN OPEN

Ignition OFF.
PCM-T connector disconnected.

Measure the resistance between:

(+) Fuel Vaporizer System Glow Plug Relay Connector, Harness Side	(-) PCM-T Connector, Harness Side
VGPRC - Pin 2	VGPRC - Pin 28

Is the resistance less than 5 ohms?

Yes	No
GO to RL5.	REPAIR the open circuit. Clear the PCM DTCs. REPEAT the self-test.

RL5 CHECK THE VGPRC CIRCUIT FOR A SHORT TO GROUND

Measure the resistance between:

(+) Fuel Vaporizer System Glow Plug Relay Connector, Harness Side	(-)
VGPRC - Pin 2	Ground

Is the resistance greater than 10K ohms?

Yes	No
GO to RL6.	REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test.

RL6 CHECK THE VGPRC CIRCUIT FOR A SHORT TO VOLTAGE

Ignition ON, engine OFF.

Measure the voltage between:

(+) Fuel Vaporizer System Glow Plug Relay Connector, Harness Side	(-)
VGPRC - Pin 2	Ground

Is any voltage present?

Yes	No
REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test.	GO to RL7.

RL7 CHECK THE FUEL VAPORIZER SYSTEM GLOW PLUG RESISTANCE

Ignition OFF.
Fuel Vaporizer System Glow Plug Assembly connector disconnected.

Measure the resistance between:

(+) Fuel Vaporizer System Glow Plug Assembly Connector, Component Side	(-) Fuel Vaporizer System Glow Plug Assembly Connector, Component Side
VGPPWR - Pin 2	GND - Pin 1

Is the resistance between 0 Ohm - 2 ohms?

Yes	No
GO to RL8.	INSTALL a new Fuel Vaporizer System Glow Plug assembly. REFER to the Service Information, Exhaust System. Clear the PCM DTCs. REPEAT the self-test.

RL8 CHECK THE VGPPWR AND VGPRM CIRCUITS FOR AN OPEN

Fuel Vaporizer System Glow Plug Relay connector disconnected.

Measure the resistance between:

(+) Fuel Vaporizer System Glow Plug Assembly Connector, Harness Side	(-) Fuel Vaporizer System Glow Plug Relay Connector, Harness Side
VGPPWR - Pin 2	VGPPWR - Pin 5

Measure the resistance between:

(+) PCM-T Connector, Harness Side	(-) Fuel Vaporizer System Glow Plug Relay Connector, Harness Side
VGPRM - Pin 26	VGPPWR - Pin 5

Are the resistances less than 5 ohms?

Yes	No
GO to RL9.	REPAIR the open circuit. Clear the PCM DTCs. REPEAT the self-test.

RL9 CHECK THE VGPPWR CIRCUIT FOR A SHORT TO VOLTAGE

Ignition ON, engine OFF.

Measure the voltage between:

(+) Fuel Vaporizer System Glow Plug Relay Connector, Harness Side	(-)
VGPPWR - Pin 5	Ground

Is any voltage present?

Yes	No
REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test.	INSTALL a new Fuel Vaporizer System Glow Plug assembly. REFER to the Service Information, Exhaust System. Clear the PCM DTCs. REPEAT the self-test.

RL10 CHECK THE VPWR VOLTAGE TO THE FUEL VAPORIZER SYSTEM FUEL PUMP

Ignition OFF.
Fuel Vaporizer System Fuel Pump Assembly connector disconnected.
Ignition ON, engine OFF.

Measure the voltage between:

(+) Fuel Vaporizer System Fuel Pump Assembly Connector, Harness Side	(-)
VPWR - Pin 1	Ground

Is the voltage greater than 10.5 V?

Yes	No
GO to RL11.	REPAIR the open circuit. Clear the PCM DTCs. REPEAT the self-test.

RL11 CHECK THE FUEL VAPORIZER SYSTEM FUEL PUMP RESISTANCE

Ignition OFF.

Measure the resistance between:

(+) Fuel Vaporizer System Fuel Pump Assembly Connector, Component Side	(-) Fuel Vaporizer System Fuel Pump Assembly Connector, Component Side
VPWR - Pin 1	VPC - Pin 2

Is the resistance between 0 - 2 ohms?

Yes	No
GO to RL12.	INSTALL a new Fuel Vaporizer System Fuel Pump assembly. REFER to the Service Information, Exhaust System. Clear the PCM DTCs. REPEAT the self-test.

RL12 CHECK THE VPC CIRCUIT FOR AN OPEN

PCM-T connector connected.

Measure the resistance between:

(+) Fuel Vaporizer System Fuel Pump Assembly Connector, Harness Side	(-) PCM-T Connector, Harness Side
VPC - Pin 2	VPC - Pin 2

Is the resistance less than 5 ohms?

Yes	No
GO to RL13.	REPAIR the open circuit. Clear the PCM DTCs. REPEAT the self-test.

RL13 CHECK THE VPC CIRCUIT FOR A SHORT TO GROUND

Measure the resistance between:

(+) Fuel Vaporizer System Fuel Pump Assembly Connector, Harness Side	(-)
VPC - Pin 2	Ground

Is the resistance greater than 10K ohms?

Yes	No
GO to RL14.	REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test.

RL14 CHECK THE VPC CIRCUIT FOR A SHORT TO VOLTAGE

Ignition ON, engine OFF.

Measure the voltage between:

(+) Fuel Vaporizer System Fuel Pump Assembly Connector, Harness Side	(-)
VPC - Pin 2	Ground

Is any voltage present?

Yes	No
REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test.	INSTALL a new Fuel Vaporizer System Fuel Pump assembly. REFER to the Service Information, Exhaust System. Clear the PCM DTCs. REPEAT the self-test.