Part 1

OBD System Description - EVAP Control System Monitor

EVPD_Continuous Purge Flow

DTC Description / Detecting Condition / Confirmation Procedure
P0496 refer to [DTC P0496: Evaporative Emission (EVAP) System Flow During Non-Purge]. P0496

Monitor Strategy Description
Test is failed if tank vacuum exceeds prescribed threshold, based on fuel level, for a prescribed time.

Malfunction Criteria
Tank vacuum greater than threshold > See table below.
AND
Fail timer greater than threshold > 2 s
































Enable Conditions
Ignition Volt greater than threshold > 10 V
AND Ignition Volt less than threshold < 16 V
AND Barometric pressure greater than threshold > 72 kPa
AND [Engine off time greater than threshold > 720 min
OR (Startup IAT-Startup ECT less than threshold < 12 °C
AND Startup ECT-Startup IAT less than threshold)] < 12 °C
AND Startup ECT greater than threshold > 0 °C
AND Startup ECT less than threshold < 40 °C
AND Startup IAT greater than threshold > 0 °C
AND Startup IAT less than threshold < 40 °C
AND Engine Run Time greater than threshold > 1 s
AND Engine Run Time less than threshold < 100 s
AND No EVPD Disabling Fault Present
(refer to disabling fault list, included with certification documentation)
Determine if Test Results Should be Reported
IF (Ambient Temperature changes are stable = TRUE
AND Fuel Slosh Effects are NOT significant) = FALSE
Then Report Test Results = TRUE
Else Do Not Report Test Results = FALSE
Verify failure not due to ambient temperature changes
IF [(Vehicle Speed greater than threshold > 37.28227153 mph
FOR Ambient Stability timer greater than threshold) > 60 s
AND (Start-up IAT - IAT less than threshold >= 3 °C
FOR an amount of time)] > 5 s
Then Ambient Temperature is stable = TRUE
Verify vapor condensation due to fuel slosh not significant enough to cause false failure
IF Vehicle Speed Threshold has been exceeded > 1.242742384 mph
AND Soak Time less than a threshold < 65535 s
AND (Minimum IAT Last Key Cycle - Start-up IAT) greater than a threshold > -15 °C
AND Post Slosh Slope Ratio is greater than a threshold > 1.75
Then Do NOT Allow Reporting = FALSE
Else Allow Reporting

Time required
N/A

EVPD_Small Leak Test

DTC Description / Detecting Condition / Confirmation Procedure
P0442 refer to [DTC P0442: Evaporative Emission (EVAP) System Small Leak Detected]. P0442

Monitor Strategy Description
If a corrected vacuum decay slope exceeds its threshold
AND
the individual segment slopes exceed their respective thresholds
AND
the segment slopes are not convex
THEN
A small leak is present

Malfunction Criteria
Corrected decay slope greater than temperature compensated threshold > see calculation below
Corrected decay slope calculation:
Uncorrected slope value
MINUS
the larger vapor correction term,
(purge leak vapor term
OR
Post decay vapor term)
Temperature Compensated Threshold:
A base term
MULTIPLIED BY
a temperature bias term x See table below.
AND
All segment slopes greater than their threshold,
(the product of a base term > See table below.
AND a temperature bias term x See table below.
AND a segment bias term) x See table below.
AND
The current segment slope minus the prior segment slope less than the convex threshold < 24.80925527 Pa/s = TRUE
































Enable Conditions
Ignition Volt greater than threshold > 10 V
AND Ignition Volt less than threshold < 16 V
AND Barometric pressure greater than threshold > 72 kPa
AND [Engine off time greater than threshold > 720 min
OR (Startup IAT-Startup ECT less than threshold < 12 °C
AND Startup ECT-Startup IAT less than threshold)] < 12 °C
AND Startup ECT greater than threshold > 0 °C
AND Startup ECT less than threshold < 40 °C
AND Startup IAT greater than threshold > 0 °C
AND Startup IAT less than threshold < 40 °C
AND Engine Run Time greater than threshold > 1 s
AND Purge enable time less than threshold < See table below.
AND Cold test timer less than threshold < 360 s
AND Fuel level greater than threshold > 0.06%
AND Fuel level less than threshold < 0.93001%
AND (Idle conditions met = TRUE
(Engine speed < threshold < 1500 rpm
AND Vehicle speed < threshold < 1.864113577 mph
AND Throttle position < threshold) < 1.001%
OR Creep conditions met = TRUE
(Engine speed < threshold < 1500 rpm
AND Vehicle speed < threshold < 3.728227153 mph
AND Throttle position < threshold)) < 1.9989%
AND Fuel not sloshing = FALSE
((Vehicle speed > threshold > 1.242742384 mph
OR Throttle position > threshold) > 1.001%
OR 125ms MAP change > threshold > 10 kPa
OR 125ms Engine speed > threshold) > 100 rpm
AND 125ms Fuel level delta > threshold) > See table below.
Purge leak vapor generation term below or equal to threshold <= See table below.
AND Post decay vapor generation term below or equal threshold <= See table below.
AND Tank concentration less than or equal to <= 89.9994%
AND No EVPD Disabling Fault Present (refer to disabling fault list, included with certification documentation) <= 89.9994%
































Time required
N/A

EVPD_Large Leak Test

DTC Description / Detecting Condition / Confirmation Procedure
P0455 refer to [DTC P0455: Evaporative Emission (EVAP) System Large Leak Detected]. P0455

Monitor Strategy Description
Test is failed if tank vacuum cannot reach prescribed vacuum after a prescribed purge volume has been drawn from the tank.

Malfunction Criteria
At idle = TRUE
AND Tank vacuum is less than threshold < 2515.698339 Pa
AND
Purge Integral greater than threshold > See table below.
OR
Not at idle = FALSE
AND
Tank Vacuum is less than threshold < 2540.756683 Pa
AND
Purge integral greater than threshold > See table below.
































Enable Conditions
Ignition Volt greater than threshold > 10 V
AND Ignition Volt less than threshold < 16 V
AND Barometric pressure greater than threshold > 72 kPa
AND Engine off time greater than threshold > 720 min
OR (Startup IAT-Startup ECT less than threshold < 12 °C
AND Startup ECT-Startup IAT less than threshold) < 12 °C
AND Startup ECT greater than threshold > 0 °C
AND Startup ECT less than threshold < 40 °C
AND Startup IAT greater than threshold > 0 °C
AND Startup IAT less than threshold < 40 °C
AND Purge enable time < threshold < See table below.
AND Engine Run Time greater than threshold > 1 s
AND Cold test timer < threshold < 360 s
AND Tank concentration <= 89.9994%
No EVPD Disabling Fault Present (refer to disabling fault list, included with certification documentation)
































Time required
N/A