Troubleshooting guide

DDEC IV TESTING

Check VPOD Wiring

The following checks should be performed for the VPOD wiring.

NOTE:

VPOD power should have been verified under the P/N check. If not, refer t o Check

Variable Output Pressure Device (VPOD) P/N and Supply Voltage..

1. Turn ignition switch ON.

2. Unplug the VPOD mating connector .

3. Insert a 1,000 ohm resistor between cavities #2 and #1 for the 12V version, or cavities

#2 and #3 for the 24V version.

4. Connect a VOM to the VPOD connector between pin #2 and pin #3 for the 12V VPOD

or pin #2 and pin #1 for the 24V VPOD.

5. Using a DDR/DDDL, activate the PWM #2 (EGR Valve) and PWM #4 (VNT), and ensure:

[a] Activating 11 % duty cycle: VDC = 90% of the VPOD supply voltage ± 1 volt

(e.g. voltage to VPOD = 13.8V * 0 .9 = 12.42V; therefore 11.42V to 1 3.42V at

PWM is okay.)

[b] Activating 90 % duty cycle: VDC = 10% of the VPOD supply voltage ± 1 volt. (e.g.

voltage to VPOD = 13.8V * 0.1 = 1.38V, therefore 0.38V to 2.38V at PWM is okay.

6. Note any air leakage when PWMs are activated to 90% and correct the leaks as needed.

[a] If both of the PWM voltage measurements are correct, replace the VPOD that had the

wrong pressure reading.

[b] If the PWM voltage measurements are incorrect, and the wiring checks are okay, try

a test ECM programmed for EGR, or contact DDC Technical Service.

5-12 All information subject to change without notice. (Rev. April 2004)