P1417-CYLINDER 7 REACTIVATION CONTROL PERFORMANCE

Theory of Operation

When all criteria has been met, power is supplied to each MDS Solenoid when the engine is making a transition from 8 cylinder mode to 4 cylinder mode. By actuating the solenoid, oil pressure is raised to the pair of lifters that coincide with each particular solenoid. The oil pressure pushes in the locking pins that allows the lifter to collapse, decoupling the valves and camshaft.

When Monitored:
Transition from 4 to 8 cylinder mode.
Set Condition:
The MDS fails to disengage for cylinder 7. One trip fault.

Possible Causes

(K454) MDS SOLENOID NO.7 CONTROL SHORT TO VOLTAGE

OIL PASSAGES RESTRICTED

LIFTER

MDS SOLENOID NO.7

PCM

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

Diagnostic Test

1. ACTIVE DTC

Ignition on, engine not running.
With a scan tool, select View DTCs.

Is the DTC Active at this time?

Yes

Go To 2

Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

2. (K454) MDS SOLENOID NO.7 CONTROL CIRCUIT SHORTED TO VOLTAGE

Turn the ignition off.
Disconnect the C3 PCM harness connector.
Disconnect the C112 In-line harness connector.

CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.

Turn the ignition on.
Measure the voltage on (K454) MDS Solenoid No.7 Control circuit in the appropriate terminal of special tool #8815.

Is voltage present?

Yes

Repair the short to voltage in the (K454) MDS Solenoid No.7 Control circuit.

Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

Go To 3

3. MDS SOLENOID RESISTANCE

Turn the ignition off.
Reconnect the C112 In-line harness connector.
Measure the resistance between the (Z42) Ground Circuit and the (K454) MDS Solenoid No.7 Control Circuit in the appropriate terminals of special tool #8815.

NOTE: It is important to follow the below temp/resistance values to ensure an accurate reading.

MDS SOLENOID RESISTANCE
TEMPERATURE VALUE ± -7° C (20° F)	RESISTANCE (OHMS) ± .25 ohms
-18° C (0° F)	8.8 ohms
0° C (32° F)	9.5 ohms
20° C (68° F)	10.3 ohms
38° C (100° F)	11 ohms
66° C (150° F)	12.2 ohms
93° C (200° F)	13.4 ohms
121° C (250° F)	14.4 ohms
149° C (300° F)	15.6 ohms

Is the resistance within an acceptable range?

Yes

Go To 4

Visually and Physically inspect the wiring harness between the C112 connector and the MDS Solenoid connector. Repair as necessary. If OK, replace the MDS Solenoid in accordance with the Service Information.

4. PCM CONTROL

Turn the ignition off.
Reconnect the PCM harness connector.
Disconnect the C112 In-line harness connector.
Ignition on, engine not running.
Using a 12-volt test light connected to the (Z42) Ground circuit, probe the (K454) MDS Solenoid No.7 Control circuit in the C112 In-line harness connector.
With a scan tool, actuate the MDS Solenoid.

Does the 12-volt test light flash on and off?

Yes

Go To 5

Replace and program the Powertrain Control Module in accordance with the Service Information. Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

5. MDS SOLENOID 7

Turn the ignition off.
Remove the Intake Manifold per Service Information.
Turn the ignition on.
With the scan tool actuate the MDS Solenoid 7.

Can you feel and hear the Solenoid Actuating?

Yes

Go To 6

Remove the Solenoid (1) and check for any debris that may be blocking the oil passages (3) to the Solenoid. If the passages are clogged, clean the passages and replace the MDS Solenoid 7. If the passages are not clogged with debris, replace the MDS Solenoid 7.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

6. OIL PASSAGES RESTRICTED

Turn the ignition off.
Remove both Solenoids on Bank 1 of the engine block.
Remove the Bank 7 Cylinder Head per Service Information.
Remove the Lifters from the right engine bank.
Inspect the oil passages to the Solenoids and from the Solenoids to the lifters.

Are the passages blocked?

Yes

Clean the oil passages as necessary. If the entire engine is restricted disassembly of the entire engine block may be necessary.

Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

Replace both sets of lifters if no other possible causes remain.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)