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P0170 HO2S Sensor System - Lambda Controller at the Limit (Bank 1)

AutoHex Online Help: Hyundai ELANTRA(HD) 2008
General Description

In order to provide the best possible combination of drivability, fuel economy and emission control, the ECM uses a closed loop air/fuel metering system. The ECM monitors the HO2S signal voltage and adjusts fuel delivery based it in closed loop fuel control. Changes in fuel delivery will be indicated by the long-term and the short-term fuel trim values. The ideal fuel trim value is around 0%. The ECM will add fuel when the HO2S signal is indicating a lean condition. Additional fuel is indicated by fuel trim values that are above 0%. The ECM will reduce fuel when the HO2S signal is indicating a rich condition. Reduction in fuel is indicated by fuel trim values that are below 0%. The DTC relevant to fuel trim will be set when the amount reaches excessive levels because of a lean or rich condition.

DTC Description

If the fuel trim values reaches the maximum or minimum threshold, then feedback control is no longer possible and emissions will be increased. The ECM sets DTC P0170 if no proportional fuel adaptation occurs for a defined time after the short term fuel trim has reached its minimum or maximum threshold.



DTC Detecting Condition

Item

Detecting Condition

Possible Cause

DTC Strategy

? Monitoring deviation of lambda controller

? Air leakage or restriction in intake or exhaust system

? Dirty engine oil or oil level too high

? Front HO2S or MAFS contamination

? Fuel system

? EVAP system

? Faulty sensor signals

Enable Conditions

? Lambda control active

? Coolant temperature > 70?(158?)

? No relevant failure

Threshold Value

? Lambda controller< -30% or >+50%

Diagnostic Time

? 30 seconds

MIL On Condition

? 2 Driving Cycles

Signal Waveform

Scan Tool Display for HO2S

Test Condition

Scan Tool Parameter

O2 SNSR VOL.-B1/S1

O2 SNSR VOL.-B1/S2

Normal Value when circuit is normal

Idle after warm up

Signal is switching from rich(above 0.45V) to lean(below 0.45V) a minimum of 3 times in 10 seconds.

above 0.7V

HO2S(B1S1) signal circuit open

Approx. 0.43~0.45V

-

HO2S(B1S2) signal circuit open

-

Approx. 0.43~0.45V

MAPS Terminal voltage with pressure

Pressure (kPa)

Approx. 20

Approx. 35

Approx. 60

Approx. 95

Approx. 101

Voltage(V)

Approx. 0.7~0.8

Approx. 1.3~1.4

Approx. 2.3~2.4

Approx. 3.7~3.8

Approx. 3.9~4.1

Scan Tool Display for TPS

Test Condition

Scan Tool Parameter

TPS VOLTAGE

Normal value with ignition "ON" & engine "OFF"

Accelerator pedal released

0.20~0.47V

Normal value with engine ON & accelerator pedal fully depressed

4.2~4.7V

Abnormal value with ignition "ON" & engine "OFF"

Power circuit open

0.01V

Ground cicuit open

4.99V

TPS signal circuit open

4.99V

TPS signal circuit short to ground

Approx. 0V

TPS signal circuit short to battery

Above 4.99V