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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1068 (Engine Controls Diagnosis - 4.8L, 5.3L, & 6.0L (DTCS P0141 To P0446)) >> Diagnosis >> DTC P0141 or P0161 (With 5.3L) >> Test Description

Test Description

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.

The number below refers to the step number on the diagnostic table.

  1. 9:  With no fault present, the test lamp will blink once per second.
DTC P0141 or P0161 (With 5.3L)

Step Action Value(s) 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 - Engine Controls? - Go to Step 2  Go to Diagnostic System Check - Engine Controls
2
IMPORTANT: Whenever the heated oxygen sensor (HO2S) heaters are commanded ON with a scan tool, they will continue to be pulsed ON once per second until the ignition is turned OFF for 30 seconds.
  1. Turn ON the ignition, with the engine OFF.
  2. Command the HO2S heaters ON with a scan tool.
  3. Wait 15 seconds to allow the HO2S heater current to stabilize.
  4. Observe the affected HO2S heater current parameter with a scan tool.
Is the HO2S heater current parameter within the specified range?		 0.25-3.125 A Go to Step 3  Go to Step 6 
3 Observe the Freeze Frame/Failure Records for this DTC.
Did the DTC fail with an engine run time of less than 10 seconds?		 - Go to Step 4  Go to Step 5 
4
  1. Operate the vehicle with the conditions for running the Heater Resistance Test.
  2. Start the engine.
Did the DTC fail this ignition?		 - Go to Step 6  Go to Intermittent Conditions
5
  1. Observe the Freeze Frame/Failure Records for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the Heater Current Test. 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 6  Go to Intermittent Conditions
6 Inspect the O2B fuse.
Is the O2B fuse open?		 - Go to Step 7  Go to Step 8 
7 Test the ignition 1 voltage circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 22  Go to Step 10 
8
  1. Disconnect the affected HO2S.
  2. Turn ON the ignition, with the engine OFF.
  3. Probe the ignition 1 voltage circuit of the HO2S harness connector on the engine harness side with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors in Wiring Systems.
Does the test lamp illuminate?		 - Go to Step 9  Go to Step 19 
9 
IMPORTANT: The test lamp may blink prior to commanding the heaters ON. This is because the heaters were commanded ON in a previous step. To command the heaters OFF, turn OFF the ignition for 30 seconds.
  1. Connect a test lamp between the ignition 1 voltage circuit of the HO2S harness connector on the engine harness side and the HO2S heater low control circuit of the HO2S harness connector on the engine harness side.
  2. Command the HO2S heaters ON with a scan tool.
Does the test lamp blink once per second?		 - Go to Step 11  Go to Step 12 
10
IMPORTANT: Perform the following test on all HO2S' which are supplied voltage by the suspect circuit.
Test the ignition 1 voltage circuit on the sensor side of the HO2S connector for a short to ground. Refer to Circuit Testing in Wiring Systems.Is any sensor shorted to ground?		 - Go to Step 20  Go to Intermittent Conditions
11 Measure the resistance of the following circuits with a DMM:
  • The HO2S heater low control circuit
  • The ignition 1 voltage circuit

Refer to Circuit Testing in Wiring Systems.
Is the resistance of either circuit more than the specified value?		 3 Ω Go to Step 18  Go to Step 16 
12 Is the test lamp on steady? - Go to Step 13  Go to Step 14 
13 Test the HO2S heater low control circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 22  Go to Step 17 
14 Test the HO2S heater low control 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 22  Go to Step 15 
15 Test the HO2S heater low control circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 22  Go to Step 17 
16 Test for shorted terminals and for poor connections at the HO2S. 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 22  Go to Step 20 
17 Test for shorted terminals and for poor connections at the powertrain control module (PCM). 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 22  Go to Step 21 
18 Repair the circuit with high resistance. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 - Go to Step 22  -
19 Repair the open or high resistance in the ignition 1 voltage circuit. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 - Go to Step 22  -
20 Replace the affected HO2S. Refer to Heated Oxygen Sensor (HO2S) Replacement Bank 1 Sensor 2 or Heated Oxygen Sensor (HO2S) Replacement Bank 2 Sensor 2 .
Did you complete the replacement?		 - Go to Step 22  -
21 Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement .
Did you complete the replacement?		 - Go to Step 22  -
22 Were you sent to this diagnostic from DTC P0140 or P0160? - Go to DTC P0140 or P0160 Go to Step 23 
23
  1. Replace the O2B fuse if necessary.
  2. Clear the DTCs with a scan tool.
  3. Turn OFF the ignition for 30 seconds.
  4. Start the engine.
  5. 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 24 
24 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 System OK
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