Suzuki SY413 Service Manual page 2695

6-1-96 ENGINE GENERAL INFORMATION AND DIAGNOSIS (G13/G16 ENGINE WITH WU TWC)
DTC P1450 BAROMETRIC PRESSURE SENSOR LOW/HIGH INPUT
DTC P1451 BAROMETRIC PRESSURE SENSOR PERFORMANCE PROBLEM
WIRING DIAGRAM/CIRCUIT DESCRIPTION
Barometric pressure sensor is installed in ECM (PCM).
DTC DETECTING CONDITION
DTC P1450:
D Barometric pressure: 136 kPa 1025 mmHg or higher, or
DTC P1451:
D Vehicle stopped
D Engine cranking
D Difference between barometric pressure and intake man-
ifold absolute pressure is 26 kPa, 200 mmHg or more
: 2 driving cycle detection logic, monitoring once/1 driving.
DTC CONFIRMATION PROCEDURE
1) Turn ignition switch OFF.
2) Clear DTC with ignition switch ON.
3) Turn ignition switch ON for 2 sec., crank engine for 2 sec. and run it at idle for 1 min.
4) Check pending DTC in "ON BOARD TEST" or "PENDING DTC" mode and DTC in "DTC" mode.
INSPECTION
DTC P1450:
Substitute a known-good ECM (PCM) and recheck.
DTC P1451:
NOTE:
Note that atmospheric pressure varies depending on weather conditions as well as altitude.
Take that into consideration when performing these check.
STEP
1 1) Connect scan tool to DLC with ignition switch
OFF.
2) Turn ignition switch ON and select "DATA LIST"
mode on scan tool.
3) Check manifold absolute pressure. See Fig. 1.
Is it barometric pressure (approx. 100 kPa,
760 mmHg) at sea level?
Fig.1 for Step 1
33 kPa 250 mmHg or lower
ACTION
POSSIBLE CAUSE
D ECM (PCM) (barometric pressure sensor) mal-
function
D Manifold absolute pressure sensor and its circuit
malfunction
D ECM (PCM) (barometric pressure sensor) mal-
function
YES
Substitute a known-
good ECM (PCM) and
recheck.
NO
Go to Step 2.