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DTC P0068 MANIFOLD PRESSURE SENSOR RANGE/PERFORMANCE

DTC P0068 MANIFOLD PRESSURE SENSOR RANGE/PERFORMANCE

OUTLINE OF DIAGNOSIS

Detect the malfunction of intake manifold pressure sensor output property. Judge NG when the intake air pressure AD value is Low whereas it seemed to be High from the viewpoint of engine condition, or when it is High whereas it seemed to be Low from the engine condition.

COMPONENT DESCRIPTION


(1)

Connector

(A)

Output voltage

(2)

Terminal

(B)

Absolute pressure

(3)

O-ring



ENABLE CONDITION

Secondary Parameters Enable Conditions
Engine coolant temperature

≥ 70°C (158°F)



GENERAL DRIVING CYCLE

Perform the diagnosis continuously after idling.

DIAGNOSTIC METHOD

Abnormality Judgment

Judge NG when either Low side or High side becomes NG. Judge NG when the continuous time of completing the malfunction criteria below becomes more than the predetermined time.

Judgment Value

Malfunction Criteria Threshold Value
Low side

Engine speed

< 2500 rpm

Throttle position

≥ 13°

Intake air amount per engine 0.5 rev.

≥ 0.55 g (0.019 oz)/rev

Output voltage

< 1.4 V

High side

Engine speed

600 ←→ 900 rpm

Throttle position

≤ 2.44°

Intake air amount per engine 0.5 rev.

< 0.5 g (0.018 oz)/rev

Output voltage

≥ 3.4 V



Time Needed for Diagnosis: Low side 3 seconds, high side 7 seconds

Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cycles.

Normality Judgment

Judge OK and clear the NG when both Low side and High side become OK. Judge OK when the malfunction criteria below are completed.

Judgment Value

Malfunction Criteria Threshold Value
Low side

Engine speed

< 2500 rpm

Throttle position

≥ 13°

Intake air amount per engine 0.5 rev.

≥ 0.55 g (0.019 oz)/rev

Output voltage

≥ 1.4 V

High side

Engine speed

600 ←→ 900 rpm

Throttle position

≤ 2.44°

Intake air amount per engine 0.5 rev.

< 0.5 g (0.018 oz)/rev

Output voltage

< 3.4 V



DTC CLEAR CONDITION


When the OK idling cycle was completed 40 times in a row

When “Clear Memory” was performed


MALFUNCTION INDICATOR LIGHT CLEAR CONDITION


When the OK driving cycle was completed 3 times in a row

When “Clear Memory” was performed


FAIL SAFE


Intake manifold pressure sensor process: Estimate the pressure from engine load.

ISC feedback: Not allowed to calculate the amount of feedback.

Heavy fuel judgment: Not allowed to carry out the heavy judgment.

Fuel cut control: Perform fuel cut when intake manifold pressure sensor is NG. (When fuel injection is large.)


ECM OPERATING AT DTC SETTING

Memorize the freeze frame data. (For test mode $02)