Suzuki GRAND VITARA XL-7 Owner's Manual page 227

6-1-66 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
TROUBLESHOOTING
Step
1 Was "ENGINE DIAG. FLOW TABLE" per-
formed?
2 HO2S-2 heater check :
1) Disconnect HO2S-2 coupler with ignition
switch OFF.
2) Check resistance between "3" and "4" termi-
nal of HO2S-2 connector.
HO2S -2 heater resistance :
11.7 – 14.3 Ω Ω Ω Ω (at 20°C (68°F))
Is it within above specification
3 HO2S heater power supply check :
1) With ignition switch ON leaving engine OFF,
check voltage between E139-3 and ground,
E139-1 and ground. (See Fig.)
Is each voltage 10 – 14 V?
4 HO2S heater control circuit check :
1) With ignition switch OFF, install HO2S
heater relay.
2) With ignition switch ON leaving engine OFF,
check voltage between C51-2-16 and
ground.
Is the voltage 10 – 14 V?
Fig. for STEP 2, 3
a. HO2S heater relay
Action Yes
Go to Step 2.
Go to Step 3.
Go to Step 4.
Substitute a known-good
ECM (PCM) and recheck.
No
Go to "ENGINE DIAG.
FLOW TABLE" in this
section.
Replace HO2S-2.
Fuse "HO2S" and/or "IG
METER" blown.
If OK, faulty "BLK/WHT"
wire or "BLU/WHT" wire.
Faulty HO2S heater relay
or "BLK" wire open, "BLU"
wire open or shorted to
ground circuit, "WHT/
BLK" wire open or shorted
to ground circuit.
If OK, substitute a known-
good ECM (PCM) and
recheck.