Dtc 1020: Master Cylinder Pressure Sensor Power Supply Failure - Suzuki Swift Sport 2004 Service & Repair Manual

DTC Troubleshooting
Step
1 Was "Electronic Stability Program Check" performed?
2 Check brake fluid level
1) Check brake fluid level in reservoir.
Is brake fluid level upper than the minimum level?
3 DTC check for ESP®
1) Connect scan tool to DLC with ignition switch turned
OFF.
2) Turn ignition switch ON and check DTC for ESP®.
Is DTC U1073 and/or U1140 detected?
4 Check brake fluid level switch
1) Turn ignition switch to OFF position.
2) Disconnect brake fluid level switch connector.
3) Check for proper connection at each terminal of brake
fluid level switch connector.
4) If OK, then check brake fluid level switch referring to
"Brake Fluid Level Switch Inspection in Section 9C".
Is check result OK?
5 Check brake fluid level switch circuit
1) Disconnect BCM connector.
2) Check for proper connection to BCM connector at "E46-
5" terminal.
3) If OK, then check resistance between "E46-5" terminal
and vehicle body ground.
Is resistance infinity?
6 Check BCM
1) Connect brake fluid level switch connector and BCM
connector.
2) Check voltage at "E46-5" terminal of BCM referring to
"Inspection of BCM and its Circuits in Section 10B".
Is voltage in good condition?

DTC 1020: Master Cylinder Pressure Sensor Power Supply Failure

DTC Detecting Condition and Trouble Area
DTC Detecting Condition
Power supply voltage to master cylinder pressure sensor
in ESP® hydraulic unit / control module assembly is out of
specification.
DTC Troubleshooting
1) Turn ignition switch to OFF position.
2) Check for proper connection from harness to ESP® control module.
3) If OK, substitute an ESP® hydraulic unit / control module assembly with correct part number.
4) Recheck system.
Action
Electronic Stability Program:
Yes
Go to Step 2.
Go to Step 3.
Go to applicable diag.
flow.
Go to Step 5.
Go to Step 6.
Substitute a known-
good ESP® hydraulic
unit / control module
assembly and recheck.
Trouble Area
• ESP® control module
4F-31
No
Go to "Electronic
Stability Program
System Check".
Replenish brake fluid to
reservoir.
Go to Step 3.
Replace brake fluid
level switch.
"BLKL/RED" wire circuit
is shorted to ground.
Check BCM power and
ground circuit. If circuit
is OK, substitute a
known-good BCM and
recheck.
S7RS0B4604028