Suzuki XL7 2007 Service Manual page 227

Circuit/System Testing
1. Ignition OFF, remove the fuse that supplies B+ to
terminal C2-56 of the ECM.
2. Disconnect the C-406 harness connector at the rear
of the fuel tank.
3. Test for less than 5.0 ohms of resistance between
the low reference circuit terminal G and ground, at
the ECM side of the connector.
➢ If greater than the specified value, test the low
reference circuit for an open/high resistance. If the
circuit/connections test normal, replace the ECM.
4. Install the fuse that supplies B+ to terminal C2-56 of
the ECM.
5. Ignition ON, test for 4.8-5.2 volts between the 5-volt
reference circuit terminal E and ground, at the ECM
side of connector C-406.
➢ If less than the specified range, test the 5-volt
reference circuit for a short to ground or open/high
resistance. If the circuit/connections test normal,
replace the ECM.
➢ If greater than the specified range, test the 5-volt
reference circuit for a short to voltage. If the circuit/
connections test normal, replace the ECM.
6. Verify that the FTP Sensor parameter is less than 4.8
volts
➢ If greater than the specified value, test the signal
circuit for a short to voltage. If the circuit/
connections test normal, replace the ECM.
7. At the ECM side of C-406, install a 3A fused jumper
wire between the signal circuit terminal F and the 5-
volt reference circuit terminal E. Verify that the FTP
Sensor parameter is greater than 4.8 volts.
➢ If less than the specified value, test the signal
circuit for a short to ground or an open/high
resistance. If the circuit/connections test normal,
replace the ECM.
8. Remove the fuel tank. Refer to "Fuel Tank
Replacement (FWD): " "Fuel Tank Replacement
(AWD): ".
9. Disconnect the FTP sensor connector
10. Inspect the FTP sensor circuits in the fuel tank
harness, between the FTP sensor connector and C-
406 for the following conditions, and repair as
necessary:
– Damaged wiring or terminals
– Open circuits
– Short to ground
– Wire to wire short
11. If all circuits/connections test normal, test or replace
the FTP sensor.
Engine General Information and Diagnosis:
Repair Instructions
Perform the "Diagnostic Repair Verification - Vehicle
Diagnostic Information: " after completing the diagnostic
procedure.
• "Fuel Tank Pressure Sensor Replacement: "
• "Control Module References: " for ECM replacement,
setup, and programming
DTC P0455
DTC Descriptor
DTC P0455: Evaporative Emission (EVAP) System
Large Leak Detected
Diagnostic Fault Information
Perform the "Diagnostic System Check - Vehicle
Diagnostic Information: " prior to using this diagnostic
procedure.
Circuit/System Description
The control module tests the evaporative emission
(EVAP) system for a large leak. The control module
monitors the fuel tank pressure (FTP) sensor signal to
determine the EVAP system vacuum level. When the
conditions for running are met, the control module
commands the EVAP canister purge valve OPEN and
the EVAP vent valve CLOSED. This allows engine
vacuum to enter the EVAP system. At a calibrated time,
or vacuum level, the control module commands the
EVAP canister purge valve closed, sealing the system,
and monitors the FTP sensor input in order to determine
the EVAP system vacuum level.
FTP Sensor Signal
Voltage
High, Approximately 1.5
Volts or More
Low, Approximately 1.5
Volts or Less
The following table illustrates the relationship between
the ON and OFF states, and the OPEN or CLOSED
states of the EVAP canister purge and vent valves.
Control Module EVAP Canister
Command Purge Valve
ON
OFF Closed
1A-122
Fuel Tank Pressure
Negative Pressure/
Vacuum
Positive Pressure
EVAP Canister
Vent Valve
Open Closed
Open