P0442 EVAP Leak Monitor Small Leak Detected
NAME OF CODEEvap System Small Leak
WHEN MONITORED
See DRB III
SET CONDITION
See DRB III
THEORY OF OPERATION
The first portion of the test determines whether or not a line is pinched in the system. If the pump rate falls to zero too rapidly, the PCM determines that there is not enough space to pressurize, this indicates a possible pinched line. If there is a leak present in the EVAP system, the cycle rate falls to a rate proportional to the size of the leak. By monitoring the cycle rate of the pump, the PCM is able to calculate the size of the leak.
POSSIBLE CAUSE
- A leak in the evaporative system between 0.040" and 0.080"
- Leak detection pump failure
SAFETY PRECAUTIONS
WARNING: Take the following precautions to prevent personal injury while using this test equipment.
Keep lighted cigarettes, sparks, flames, and other ignition sources away from the test area to prevent the ignition of explosive gases. Keep the test area well-ventilated.
This equipment is designed to be used on the vehicle evaporative system only. Using the equipment in a manner for which it was not designed could be a dangerous procedure.
The vehicle fuel tank must be 1/2 full of gas when conducting this test procedure. Pressurizing a tank containing less than three gallons of gas could result in the ignition of fumes, causing an explosion.
Wear protective eyewear that meets the requirements of OSHA and ANSI Z87.1-1968.
When using the battery as a power source, connect the AFD(+) battery clip to the positive vehicle battery terminal, and connect the BLACK (-) battery clip to a good ground away from the battery.
If the vehicle being tested is not on a hoist, set the parking brake and block the wheels before starting the teat
EVAPORATIVE SYSTEM PRESSURE TEST
Warning: Verify the vehicle fuel tank contains at least 3 gallons of fuel.
1 Attach the DRB III to the vehicle.
2 Turn the key on.
3 At: ENGINE SYSTEM TESTS select: LEAK DETECTION PUMP TEST
4 Read instructions and then press ENTER.
5 At: LEAK DETECTION PUMP TEST select #3 HOLD PSI.
6 At the vacuum hose going to LDP attach and apply a continuous vacuum (i.e. 20" Hg).
7 Remove get cap.
8 Install 6922 on the gas cap and on the vehicle.
9 Attach the supply hose from 6872A to 6922.
10 Attach the power source from the 6872A, clip to battery and ground clip 10 battery.
11 On the 6072A set the Pressure/Hold valve to open and set the Vent valve to closed.
12 Turn the timer on and watch the gauge.
13 When the gauge pressure reaches 14 in. H2O, turn the Pressure/Hold valve to closed.
14 Turn the timer off. Note the time and pressure.
15 Does the pressure drop more than 6 inches (108 inches H2O on the gauge) in 2 minutes?
18 If not, the system is OK.
17 If it does, then there is a leak in the system.