LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 2005 >> Venture LS >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - 3.4L DTC P0140 To P0443 >> DTC Tests >> DTC P0404 >> Diagnostic Aids

Diagnostic Aids

DTC P0404

Step Action Values Yes No
Schematic Reference:  Engine Controls Schematics 
Connector End View Reference:  Engine Controls Connector End Views  or  Powertrain Control Module (PCM) Connector End Views 
1 Did you perform the Diagnostic System Check - Vehicle? - Go to Step 2  Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2 Is DTC P0403, P0405, or P0406 also set? - Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information Go to Step 3 
3
  1. Turn ON the ignition, with the engine OFF.
  2. Command the EGR valve from 0 percent to 100 percent with a scan tool.
Does the EGR Position Sensor parameter remain within 15 percent of the desired EGR Position parameter when commanded with a scan tool?		 - Go to Step 4  Go to Step 5 
4
  1. Observe the Freeze Frame/Failure Records data for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. 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 5  Go to Diagnostic Aids
5
  1. Turn OFF the ignition.
  2. Disconnect the exhaust gas recirculation (EGR) valve.
  3. Turn ON the ignition, with the engine OFF.

  4. Observe the EGR Position Sensor parameter with a scan tool.

Is the EGR position sensor parameter less than the specified value?		 1% Go to Step 6  Go to Step 11 
6 Connect a test lamp between the 5-volt reference circuit of the EGR valve and the low reference circuit of the EGR valve.
Does the test lamp illuminate?		 - Go to Step 7  Go to Step 8 
7
  1. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the EGR valve and the EGR valve position signal circuit.
  2. Observe the EGR Position Sensor parameter on the scan tool.
 Is the EGR Position Sensor parameter more than the specified value?		 99% Go to Step 9  Go to Step 13 
8 Connect a test lamp between the 5-volt reference circuit of the EGR valve and a good ground.
Does the test lamp illuminate?		 - Go to Step 12  Go to Step 14 
9
IMPORTANT: If the scan tool output control function times out, re-command the EGR valve to 100 percent before the next electrical measurement is taken.
  1. Command the EGR valve to 100 percent with a scan tool.
  2. Measure the voltage from the EGR high control circuit to a good ground. Note the results in volts as "supply voltage".
  3. Connect a jumper wire between the EGR low control circuit and the corresponding terminal on the EGR valve.
  4. Connect a DMM between the EGR high control circuit and the corresponding terminal on the EGR valve.
  5. Measure the note and current draw in amps.
  6. Remove the DMM from the EGR high control circuit.
  7. Connect a jumper wire between the EGR high control circuit and the corresponding terminal on the EGR valve.
  8. Connect a DMM in parallel between the EGR high control circuit and a good ground.
  9. Measure the voltage drop in volts and note as "load voltage drop".
  10. Subtract the load voltage drop from the supply voltage then divide the answer by the current draw. The result is the amount of resistance in the EGR high control circuit.
Is the calculated resistance more than the specified value?		 3 Ω Go to Step 15  Go to Step 10 
10
IMPORTANT: If the scan tool output control function times out, re-command the EGR valve to 100 percent before the next electrical measurement is taken.
  1. Connect a DMM in parallel between the EGR low control circuit and a good ground.
  2. Measure the voltage drop in volts and not as "low control voltage drop".
  3. Divide the low control voltage drop by the current draw. The result is the amount of resistance in the low control circuit.
Is the calculated resistance more than the specified value?		 3 Ω Go to Step 16  Go to Step 17 
11 Test the EGR valve position signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 21  Go to Step 18 
12 Test the low reference circuit of the EGR valve for an open or for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 21  Go to Step 18 
13 Test the EGR valve position signal circuit for the following conditions:
  • An open
  • A short to ground
  • High resistance

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 21  Go to Step 18 
14
  1. Test the 5-volt reference circuit of the EGR valve for an open or for high resistance.
  2. Refer to Circuit Testing andWiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 21  Go to Step 18 
15 Test the high control circuit of the EGR valve for resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 21  Go to Step 18 
16 Test the low control circuit of the EGR valve for resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 21  Go to Step 18 
17 Test for an intermittent and for a poor connection at the EGR valve. Refer to Testing for Intermittent Conditions and Poor Connections andRepairing Connector Terminals in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 21  Go to Step 19 
18 Test for an intermittent and for a poor connection at the powertrain control module (PCM). Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals in Wiring Systems.
Did you find and correct the condition?		 - Go to Go to Step 21  Go to Step 20 
19 Replace the EGR valve. Refer to Exhaust Gas Recirculation (EGR) Valve Replacement .
Did you complete the replacement?		 - Go to Step 21  -
20 Replace the PCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.
Did you complete the replacement?		 - Go to Step 21  -
21
  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 22 
22 Observe the Capture Info with a scan tool.
Are there any DTCs that have not been diagnosed?		 - Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information System OK
scientia non olet · About LEMON Manuals