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Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1047 (Engine Controls Diagnosis - 6.6L (LLY) (DTC P0238 To DTC P0652)) >> Diagnosis >> DTC P0370 or P0374 >> Diagnostic Aids

Diagnostic Aids

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

A missing high resolution signal will cause a no-start condition. High resistance in the position sensor low reference circuit may cause this DTC to set. If the condition is intermittent, refer to Intermittent Conditions .

DTC P0370 or P0374

Step Action Values Yes No
Schematic Reference:  Engine Controls Schematics 
Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views
1 Did you perform the Diagnostic System Check - Engine Controls? - Go to Step 2  Go to Diagnostic System Check - Engine Controls
2
  1. Crank the engine.
  2. Observe the Specific DTC information with the scan tool for the DTC that was set.
Does the scan tool display Last Test Failed?		 - Go to Step 3  Go to Diagnostic Aids
3
IMPORTANT: Use the proper terminal from J 35616  Connector Test Adapter Kit.
  1. Turn OFF the ignition.
  2. Disconnect the fuel injection control module (FICM) harness connector containing the engine speed signal circuit.
  3. Connect a DMM between the engine speed signal circuit and a good ground. Refer to Troubleshooting with a Digital Multimeter in Wiring Systems.
  4. Measure the voltage while cranking the engine.
Does the voltage measure within the specified range?		 5.5-6.3 V Go to Step 5  Go to Step 4 
4 Does the voltage measure above the specified range? 5.5-6.3 V Go to Step 6  Go to Step 7 
5 Test for a short to reference voltage on the engine speed signal circuit. Refer to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 12  Go to Step 8 
6
  1. Test for a short to voltage in the engine speed signal circuit.
  2. Repair as necessary. Refer to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 12  Go to Step 10 
7
  1. Test the engine speed signal circuit for an open or a short to ground.
  2. Repair as necessary. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 12  Go to Step 10 
8 Test for a poor connection at the FICM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 12  Go to Step 9 
9 Replace the FICM. Refer to Fuel Injection Control Module Replacement .
Did you complete the replacement?		 - Go to Step 12  -
10 Test for a poor connection at the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 12  Go to Step 11 
11 Replace the ECM. Refer to Engine Control Module (ECM) Replacement .
Did you complete the replacement?		 - Go to Step 12  -
12
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Did the DTC fail this ignition?		 - Go to Step 2  Go to Step 13 
13 Observe the Capture Info with a scan tool.
Have any other DTCs not been diagnosed?		 - Go to Diagnostic Trouble Code (DTC) List System OK
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