Dtc P1450/P1451 Barometric Pressure Sensor Circuit Malfunction/Performance Problem - Suzuki GRAND VITARA XL-7 Owner's Manual

DTC P1450/P1451 Barometric Pressure Sensor Circuit Malfunction/Perfor-
mance Problem
SYSTEM DESCRIPTION
Barometric pressure sensor is installed in ECM (PCM).
DTC DETECTING CONDITION AND TROUBLE AREA
DTC DETECTING CONDITION
DTC P1450 :
Barometric pressure out of specification is detected.
DTC P1451 :
While running under conditions described for "DTC CONFIRMATION
PROCEDURE", barometric pressure value compared with intake
manifold vacuum value in fuel cut state is not as specified.
(2 driving cycle detection logic)
DTC CONFIRMATION PROCEDURE
For DTC P1450
1) Connect scan tool to DLC with ignition switch OFF.
2) Turn ON ignition switch and clear DTC by using scan tool and run engine for 1 min.
3) Check DTC by using scan tool.
For DTC P1451
WARNING:
• When performing a road test, select a place where there is no traffic or possibility of a traffic acci-
dent and be very careful during testing to avoid occurrence of an accident.
• Road test should be carried out with 2 persons, a driver and a tester, on a level road.
1) Connect scan tool to DLC with ignition switch OFF.
2) Turn ON ignition switch and clear DTC, pending DTC and freeze frame data by using scan tool and warm up
engine to normal operating temperature.
3) Increase engine speed to 3,000 r/min. in 3rd gear in case of M/T and "2" range in case of A/T.
4) Release accelerator pedal and with engine brake applied, keep vehicle coasting for 5 sec. or more (keep fuel
cut condition for 5 sec. or more). If fuel cut condition is not kept for 5 sec. or more, coast down a slope in
engine speed 1600 – 3000 r/min for 5 sec. or more.
5) Stop vehicle and run engine at idle.
6) Repeat steps 3) – 5) 2 times.
7) Check pending DTC by using scan tool.
TROUBLESHOOTING (DTC P1450/P1451)
Step
1 Was "ENGINE DIAG. FLOW TABLE" performed?
2 Is DTC P1451 set?
3 MAP sensor check :
1) Check MAP sensor and its circuit referring to
Steps 2 and 3 of "DTC P1408 Diag. Flow Table".
Is check result satisfactory?
ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE) 6-1-113
Action
TROUBLE AREA
• Barometric pressure sensor in ECM
(PCM)
• Manifold absolute pressure sensor
performance problem
• Barometric pressure sensor in ECM
(PCM)
Yes
Go to Step 2. Go to "ENGINE DIAG. FLOW
TABLE" in this section.
Go to Step 3. Substitute a known-good
ECM (PCM) and recheck.
Substitute a MAP sensor or its circuit mal-
known-good function.
ECM (PCM) and
recheck.
No