Isuzu KB P190. Manual - part 842

 

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Isuzu KB P190. Manual - part 842

 

 

Engine Management – V6 – Diagnostics 

Page 6C1-2–90 

 

Step Action 

Yes 

No 

2 

N O T E  

•  DTC P0133 is for bank 1 sensor 1 and DTC P0153 is 

for bank 2 sensor 1. 

•  DTC P0132 causes DTC P0153 to set. If DTC P0132 

is set with DTC P0153, refer to 7.10 

DTC 

P0130, P0131, P0132, P0135, P0137, P0138, P0140, 
P0141, P0150 P0151, P0152, P0155, P0157, P0158, 
P0160, P0161, P2243, P2247, P2270, P2271, P2272, 
P2273, P2297 or P2298 in this Section. 

•  Inspect the heated oxygen sensor (HO2S) for being 

secure before proceeding with this DTC. A sensor that 
is loose could cause this DTC to set. 

1 

Start engine and allow to reach operating temperature. 

2 

Observe the diagnostic trouble code (DTC) information with 
Tech 2. 

Did DTC P0133 and / or DTC P0153 fail this ignition cycle? 

Go to Step 4 

Go to Step 3 

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 Additional 

Information in this 

DTC 

4 

Did DTC P0133 and DTC P0153 fail this ignition cycle? 

Go to Step 7 

Go to Step 5 

5 

1 

Inspect for an exhaust leak near the HO2S. Refer to 6F Exhaust 
System – V6. After you inspect the exhaust system, return to 
this diagnostic. 

Did you find and correct the condition? 

Go to Step 8 

Go to Step 6 

6 

1 

Inspect or test for the following conditions: 

• 

Inspect that the HO2S is securely installed. 

• 

Inspect for corrosion on the HO2S terminals. 

• 

Inspect the terminal tension at the HO2S and at the 
engine control module (ECM). Refer to 8A Electrical-Body 
and Chassis. 

• 

Inspect the HO2S wiring for damage. 

Did you find and correct the condition? 

Go to Step 8 

Go to Step 7 

Engine Management – V6 – Diagnostics 

Page 6C1-2–91 

 

Step Action 

Yes 

No 

7 

N O T E  

If both DTCs are set, determine and correct the cause of 
the contamination before replacing a sensor. 

1 

Inspect for the following conditions: 

• 

Fuel contamination – refer to 6.5  Alcohol / Contaminants 
in Fuel Diagnosis in this Section. 

• 

The correct RTV sealant.  

• 

Engine oil consumption – refer to 6A1 Engine Mechanical 
– V6. 

• 

Engine coolant consumption – refer to 6B1 Engine Cooling 
– V6. 

2 

Replace the HO2S. Refer to 6C1-3 Engine Management – V6 – 
Service Operations. 

Did you complete the replacement? 

Go to Step 8 

— 

8 

1 

Use Tech 2 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. 
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 9 

9 

1 

Using Tech 2, select the DTC display function. 

Does Tech 2 display any DTCs? 

Go to the 

appropriate DTC 

Table in this Section 

System OK 

When all diagnosis and repairs are completed, clear all DTCs and verify correct operation 

7.12  DTC P0139 or P0159 

DTC Descriptors 

This diagnostic procedure supports the following DTCs: 

• 

DTC P0139 – O2 Sensor Circuit Slow Response (Bank 1 Sensor 2) 

• 

DTC P0159 – O2 Sensor Circuit Slow Response (Bank 2 Sensor 2) 

Circuit Description 

The post catalytic converter heated oxygen sensor (HO2S) produces a voltage that varies between 100 – 900 mV under 
normal operating conditions. The engine control module (ECM) produces a bias voltage on the HO2S signal circuit of 
420 – -480 mV. The reference ground for the sensor is provided through the ECM. 

The ECM monitors the signal voltage to determine if the exhaust is lean or rich. The oxygen sensor voltage is high when 
the exhaust is rich, and low when the exhaust is lean. The ECM constantly monitors the HO2S signal during the Closed 
Loop operation. If the ECM detects that the decel fuel cut-off rich-to-lean transition time is too long, DTC P0139 will set 
for bank 1 sensor 2, or DTC P0159 will set for bank 2 sensor 2. 

Conditions for Running the DTC 

• 

DTCs P0021, P0024, P0030, P0031, P0032, P0036, P0037, P0038, P0050, P0051, P0052, P0056, P0057, P0058, 
P0101, P0102, P0103, P0106, P0107, P0108, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, 
P0131, P0132, P0135, P0137, P0138, P0139, P0140, P0141, P0151, P0152, P0155, P0157, P0158, P0159, 
P0160, P0161, P0201-P0208, P0221, P0222, P0223, P0261, P0262, P0264, P0265, P0267, P0268, P0270, 
P0271, P0273, P0274, P0276, P0277, P0279, P0280, P0282, P0283, P0300, P0301-P0308, P0335, P0336, 

Engine Management – V6 – Diagnostics 

Page 6C1-2–92 

 

P0340, P0341, P0345, P0346, P0351-P0358, P0365, P0366, P0390, P0391, P0442, P0443, P0446, P0449, 
P0453, P0454, P0455, P0458, P0459, and P0496 are not set.  

• 

The ECT Sensor parameter is more than 66° C.  

• 

The Vehicle Speed Sensor parameter is between 5 – 180 km/h.  

• 

The calculated catalytic converter temperature is more than 520° C.  

• 

DTC P0139 or P0159 runs continuously once the above conditions are met.  

Conditions for Setting the DTC 

• 

The ECM detects that the decel fuel cut-off and rich-to-lean transition time has exceeded 1 second. 

Action Taken When the DTC Sets 

• 

The ECM illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the 
diagnostic runs and fails.  

• 

The ECM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the 
control module stores this information in the Failure Records. If the diagnostic reports a failure on the second 
consecutive ignition cycle, the control module records the operating conditions at the time of the failure. 

• 

The ECM writes the operating conditions to the Freeze Frame and updates the Failure Records. 

Conditions for Clearing the MIL/DTC 

• 

The ECM turns OFF the malfunction indicator lamp (MIL) after three consecutive ignition cycles that the diagnostic 
runs and does not fail.  

• 

A current DTC, Last Test Failed, clears when the diagnostic runs and passes.  

• 

A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission 
related diagnostic.  

• 

Use Tech 2 to clear the MIL and the DTC. 

DTC P0139 or P0159 Diagnostic Table 

Step Action  Value(s) 

Yes 

No 

1 

Has the Diagnostic System Check been completed? 

— 

Go to Step 2 

Refer to  

4.4 Diagnostic 

System Check 

2 

1 

Start and run the engine until normal operating 
temperature is reached. 

2 

Quickly cycle the throttle from closed throttle to 
wide open throttle (WOT) 3 times within 
5 seconds while observing the HO2S Bank 1 
Sensor 2 or HO2S Bank 2 Sensor 2 voltage 
parameter with Tech 2. 

Does the voltage react immediately when performing 
the above action? 

— 

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 5.2

 Intermittent 

Fault Conditions in 

this Section. 

Engine Management – V6 – Diagnostics 

Page 6C1-2–93 

 

4 

1 Ignition 

OFF. 

2 

Disconnect the affected heated oxygen sensor 
(HO2S) 2 

3 

Connect a 3 Amp fused jumper wire between the 
HO2S high signal circuit, on the engine harness 
side connector, and a good ground. 

4 

Ignition ON, engine OFF. 

5 

Use Tech 2 to observe the affected HO2S 2 
parameter  

Is the voltage less than the specified value? 

25 mV 

Go to Step 5 

Go to Step 7 

5 

1 

Remove the jumper wire from the previous step.

2 

Connect a 3 Amp fused jumper wire between the 
HO2S high signal circuit and the HO2S low 
signal circuit, on the engine harness side 
connector. 

3 

Use Tech 2 to observe the HO2S 2 parameter. 

Is the voltage less than the specified value? 

25 mV 

Go to Step 6 

Go to Step 8 

6 

1 

Remove the jumper wire from the previous step.

2 

Measure the resistance of the following circuits 
with a DMM: 

• 

The HO2S heater low control circuit. 

• 

The ignition voltage circuit Refer to 8A 
Electrical-Body and Chassis. 

Is the resistance of either circuit more than the 
specified value? 

5 

Ω 

Go to Step 12 

Go to Step 9 

7 

1 

Test the HO2S high signal circuit for an open or 
high resistance. Refer to 8A Electrical-Body and 
Chassis. 

Did you find and correct the condition? 

— 

Go to Step 15 

Go to Step 11 

8 

1 

Test the HO2S low signal circuit for an open or 
high resistance. Refer to 8A Electrical-Body and 
Chassis.  

Did you find and correct the condition? 

— 

Go to Step 15 

Go to Step 11 

 

 

 

 

 

 

 

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