LEMON Manuals: Even more car manuals for everyone
Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1044 (Engine Controls Diagnosis - 6.6L (Lb7) (DTCS P0237 To P0611)) >> 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.

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. Use the scan tool to observe the Specific DTC information for the DTC that was set.
Does the scan tool display Last Test Failed?		 - Go to Step 3  Go to Intermittent Conditions
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. Measure the voltage from the engine speed signal circuit at the FICM harness connector to a good ground using an adapter terminal and a DMM. Refer to Troubleshooting with a Digital Multimeter in Wiring Systems.
  4. Crank the engine
Does the voltage measure within the specified range?		 4-5 V Go to Step 4  Go to Step 5 
4 With the DMM still connected, measure the current from the engine speed signal circuit to a good ground.
Does the current measure less than the specified value?		 10 mA Go to Step 9  Go to Step 6 
5 Does the voltage measure above the specified range? 4-5 V Go to Step 7  Go to Step 8 
6 Repair the short to reference voltage on the engine speed signal circuit. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 - Go to Step 13  -
7
  1. Test for a short to battery voltage, ignition voltage, or either 5-volt reference on 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 13  Go to Step 11 
8
  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 13  Go to Step 11 
9
  1. Inspect for poor connections at the FICM. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
  2. Repair as necessary. Refer to Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 13  Go to Step 10 
10 Replace the fuel injection control module. Refer to Fuel Injection Control Module Replacement .
Did you complete the replacement?		 - Go to Step 13  -
11
  1. Inspect for poor connections at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
  2. Repair as necessary. Refer to Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 13  Go to Step 12 
12 Replace the ECM. Refer to Engine Control Module (ECM) Replacement .
Did you complete the replacement?		 - Go to Step 13  -
13
  1. Use the scan tool in order to clear the DTCs.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
Does the DTC run and pass?		 - Go to Step 14  Go to Step 2 
14 With a scan tool, observe the stored information, Capture Info.
Does the scan tool display any DTCs that you have not diagnosed?		 - Go to Diagnostic Trouble Code (DTC) List System OK
scientia non olet · About LEMON Manuals