Suzuki Wagon R Manual page 1181

DTC P1500 ENGINE STARTER SIGNAL CIRCUIT MALFUNCTION
CIRCUIT DESCRIPTION
Main
fuse
DTC DETECTING CONDITION
D High voltage at terminal E23-16 for 3 min. after engine
start.
D Low voltage at terminal E23-16 during starting engine.
2 driving cycle detection logic, continuous monitoring.
DTC CONFIRMATION PROCEDURE
1) Turn ignition switch OFF.
2) Clear DTC with ignition switch ON, crank engine and run it at idle for 3 min.
3) Check pending DTC in "ON BOARD TEST" or "PENDING DTC" mode and DTC in "DTC" mode.
INSPECTION
STEP
1 Was "ENGINE DIAG. FLOW TABLE" performed?
2 Check for voltage at terminal E23-16 of ECM
(PCM) connector connected, under following
condition.
While engine cranking : 6 – 10 V
After starting engine
Is voltage as specified?
Ignition
switch
(starter
switch)
ACTION
: 0 V
GENERAL INFORMATION AND ENGINE DIAGNOSIS 6-1-89
Starter
POSSIBLE CAUSE
D "BLK/YEL" circuit open
D ECM (PCM) malfunction
YES
Go to Step 2.
Poor E23-16
connection or
intermittent trouble.
Check for intermittent
referring to "Intermittent
and Poor Connection"
in Section 0A.
If wire and connections
are OK, substitute a
known-good ECM (PCM)
and recheck.
NO
Go to "ENGINE DIAG.
FLOW TABLE".
"BLK/YEL" circuit open.