LEMON Manuals: Even more car manuals for everyone
Home >> Hummer >> 2008 >> H2 4D Utility Wagon >> Repair and Diagnosis >> External Pages >> Different car >> Section 44 (Rear Drive Axle) >> Diagnostic Information and Procedures >> DTC C0388 >> Test Description

Test Description

WARNING: This page is about a different car, the 2007 Hummer H2. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step numbers on the diagnostic table.

  1. 2:  This step determines of the coil has excessive resistance or if the windings are shorted together.
  2. 3:  This step determines if the coil or pigtail is shorted to ground.
  3. 4:  This step determines if either the differential lock control or differential lock return circuits are shorted to ground.
  4. 5:  This step determines if the differential lock control and differential lock return circuits are shorted together.
  5. 6:  This step tests for an open or high resistance in both the return and control circuits.
  6. 7:  This step refers to transfer case shift control module replacement.
  7. 8:  This step refers to encoder motor replacement.
DTC C0388

Step Action Value (s) Yes No
Schematic Reference:  Transfer Case Control Schematics 
Connector End View Reference:  Rear Axle Connector End Views  
1 Did you perform the Diagnostic System Check - Vehicle? - Go to Step 2  Go to Diagnostic System Check - Vehicle
2 
  1. Disconnect the rear differential lock harness from the rear differential lock coil pigtail.
  2. With a DMM, measure the resistance of the rear differential lock coil and pigtail by probing the rear differential lock return and the rear differential lock control circuits.
Was the resistance reading within the specified values?		 2.2-4.3 Ω Go to Step 3  Go to Step 8 
3  With the connector still disconnected, with a DMM, probe the return then the control circuits and check for resistance to ground.
Did the DMM indicate a short to ground?		 - Go to Step 8  Go to Step 4 
4 
  1. Disconnect connector C1 from the transfer case shift control module.
  2. Disconnect the rear differential lock harness from the rear differential coil pigtail.
  3. With a DMM, check for a short to power or short to ground on the differential lock control and differential lock return circuits. Refer to Circuit Testing and Wiring Repairs .
Was the condition found and corrected?		 - Go to Step 9  Go to Step 5 
5 
IMPORTANT: This circuit contains a reversed bias diode. The red lead of the DMM must be placed on the rear differential lock high control circuit, and the black lead on the rear differential lock low reference circuit. This is done to avoid showing the circuits falsely shorted together.
Check the differential lock control and the differential lock return circuits for being shorted together. Refer to Circuit Testing and Wiring Repairs .Was the condition found and corrected?		 - Go to Step 9  Go to Step 6 
6  Check the suspect circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs .
Was the condition found and corrected?		 - Go to Step 9  Go to Step 7 
7  Replace the transfer case shift control module. Refer to Control Module References for replacement, setup, and programming.
Was the repair completed?		 - Go to Step 9  -
8  Replace the rear differential lock coil. Refer to Locking Differential Coil Assembly Replacement .
Was the repair completed?		 - Go to Step 9  -
9
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
Does the DTC reset?		 - Go to Step 1  System OK
scientia non olet · About LEMON Manuals