LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Suzuki >> 2004 >> Swift + >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - 1.6L (L91) (DTC P0106 To DTC P0217) >> Diagnostic Information & Procedures >> DTC P0140 >> Test Description
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Test Description

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

  1. 4:  This step tests for a short to voltage to the signal circuit of the HO2S 2.
  2. 5:  This step tests the HO2S 2 signal and the low reference circuit for an open. The HO2S voltage should go low.
DTC P0140

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. Start the engine.
  2. Allow the engine to reach the normal operating temperature.
  3. Operate the engine above 1,200 RPM for 30 seconds and then allow the engine to idle.
  4. Observe the heated oxygen sensor (HO2S) 2 voltage parameter with a scan tool.
Does the voltage fluctuate above and below the specified range?		 422-478 mV Go to Step 3  Go to Step 4 
3
  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 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 4  Go to Intermittent Conditions
4 
  1. Turn OFF the ignition.
  2. Disconnect the HO2S 2 sensor.
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a test lamp from the signal circuit of the HO2S 2 to a good ground.
Does the test lamp illuminate?		 - Go to Step 7  Go to Step 5 
5 
  1. Connect a 3-ampere fused jumper wire between the signal circuit and the low reference circuit of the HO2S 2.
  2. Start the engine.
  3. Observe the HO2S 2 voltage parameter with a scan tool.
Is the voltage less than the specified value?		 20 mV Go to Step 9  Go to Step 6 
6
  1. Connect a 3-ampere fused jumper wire between the HO2S 2 signal circuit and a good ground.
  2. Observe the HO2S 2 voltage parameter with a scan tool.
Is the voltage less than the specified value?		 20 mV Go to Step 8  Go to Step 7 
7 Test the HO2S 2 signal circuit for one of the following conditions:
  • A short to voltage
  • An open
  • High resistance

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 13  Go to Step 10 
8 Test the HO2S 2 low reference circuit for one of the following conditions:
  • A short to voltage
  • An open
  • High resistance

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 13  Go to Step 10 
9 Test for an intermittent and poor connections at the harness connector of the HO2S 2. 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 13  Go to Step 11 
10 Test for an intermittent and poor connection at the engine control module (ECM). 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 Step 13  Go to Step 12 
11 Replace the HO2S 2. Refer to Heated Oxygen Sensor Replacement - Position 2 .
Did you complete the replacement?		 - Go to Step 13  -
12 Replace the ECM. Refer to Engine Control Module (ECM) Replacement .
Did you complete the replacement?		 - Go to Step 13  -
13
  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 14 
14 Observe the Capture Info with a scan tool.
Are there any DTCs that have not been diagnosed?		 - Go to Diagnostic Trouble Code (DTC) List System OK
scientia non olet · About LEMON Manuals