Hummer H1 (2002+). Manual — part 120

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Brake System 7-39

®

05745159

4-13

Left rear

wheel

speed sensor
open circuit.

18 and 35

500-2000

W

Check electrical resistance of affected sensor and
wiring at ECU connector and at harness plugs.
Repair wiring or replace sensor as necessary.

4-14

Left front

wheel speed
sensor open cir-
cuit.

15 and 32

500-2000

W

Check electrical resistance of affected sensor and
wiring at ECU connector and at harness plugs.
Repair wiring or replace sensor as necessary.

4-15

Right rear

wheel speed
sensor open cir-
cuit.

16 and 33

500-2000

W

Check electrical resistance of affected sensor and
wiring at ECU connector and at harness plugs.
Repair wiring or replace sensor as necessary.

5-0

Short circuit to
battery between
ECU and right
front inlet

valve solenoid
or wiring.

6 and 27

0 volts

5.0-7.5

W

Check voltages at wiring harness including con-
nectors. Check electrical resistance of affected
valve wiring to ground at ECU connector and at
modulator assembly plug. Repair wiring or
replace as necessary.

5-1

Short circuit to
battery between
ECU and right
front outlet

valve solenoid
or wiring.

7 and 27

0 volts

3.0-5.0

W

Check voltages at wiring harness including con-
nectors. Check electrical resistance of affected
valve wiring to ground at ECU connector and at
modulator assembly plug. Repair wiring or
replace as necessary.

5-2

Short circuit to
battery between
ECU and left
front inlet

valve solenoid
or wiring.

23 and 27

0 volts

5.0-7.5

W

Check voltages at wiring harness including con-
nectors. Check electrical resistance of affected
valve wiring to ground at ECU connector and at
modulator assembly plug. Repair wiring or
replace as necessary.

5-3

Short circuit to
battery between
ECU and left
front outlet

valve solenoid
or wiring.

24 and 27

0 volts

3.0-5.0

W

Check voltages at wiring harness including con-
nectors. Check electrical resistance of affected
valve wiring to ground at ECU connector and at
modulator assembly plug. Repair wiring or
replace as necessary.

5-4

Short circuit to
battery between
ECU and right
rear inlet

valve

solenoid or wir-
ing.

4 and 27

0 volts

5.0-7.5

W

Check voltages at wiring harness including con-
nectors. Check electrical resistance of affected
valve wiring to ground at ECU connector and at
modulator assembly plug. Repair wiring or
replace as necessary.

Fault Code List

Ignition key “OFF” to test system (except where noted)

Fault Code

Problem Area

Test Pin

Locations

Values

Check/Repair

7-40

Brake System

_____________________________________________________________

®

5-5

Short circuit to
battery between
ECU and right
rear outlet

valve solenoid
or wiring.

5 and 27

0 volts

3.0-5.0

W

Check voltages at wiring harness including con-
nectors. Check electrical resistance of affected
valve wiring to ground at ECU connector and at
modulator assembly plug. Repair wiring or
replace as necessary.

5-6

Short circuit to
battery between
ECU and left
rear inlet

valve

solenoid or wir-
ing.

21 and 27

0 volts

5.0-7.5

W

Check voltages at wiring harness including con-
nectors. Check electrical resistance of affected
valve wiring to ground at ECU connector and at
modulator assembly plug. Repair wiring or
replace as necessary.

5-7

Short circuit to
battery between
ECU and left
rear outlet

valve solenoid
or wiring.

22 and 27

0 volts

3.0-5.0

W

Check voltages at wiring harness including con-
nectors. Check electrical resistance of affected
valve wiring to ground at ECU connector and at
modulator assembly plug. Repair wiring or
replace as necessary.

5-8

Short circuit to
battery +
between ECU
and RCP relay
1.

11 and 27

0 volts

Check wiring harness between ECU and relay and
pump ground connections. Repair wiring as nec-
essary.

5-9

Short circuit to
battery +
between ECU
and RCP relay
2.

12 and 27

0 volts

Check wiring harness between ECU and relay and
pump ground connections. Repair wiring as nec-
essary.

5-12

Right front

wheel speed
signal is erratic.

17 and 34

Greater than 0.9

volts AC at one

tire revolution

per second.

Check for damaged tone wheel, incorrect sensor
adjustment, excessive tone wheel runnout
(> .041"), excessive geared hub input bearing play
and tire size mismatch. Repair or replace as neces-
sary.

5-13

Left rear

wheel

speed signal is
erratic.

18 and 35

Greater than 0.9

volts AC at one

tire revolution

per second.

Check for damaged tone wheel, incorrect sensor
adjustment, excessive tone wheel runnout
(> .041"), excessive geared hub input bearing play
and tire size mismatch. Repair or replace as neces-
sary.

5-14

Left front

wheel speed
signal is erratic.

15 and 32

Greater than 0.9

volts AC at one

tire revolution

per second.

Check for damaged tone wheel, incorrect sensor
adjustment, excessive tone wheel runnout
(> .041"), excessive geared hub input bearing play
and tire size mismatch. Repair or replace as neces-
sary.

Fault Code List

Ignition key “OFF” to test system (except where noted)

Fault Code

Problem Area

Test Pin

Locations

Values

Check/Repair

____________________________________________________________

Brake System 7-41

®

05745159

5-15

Right rear

wheel speed
signal is erratic.

16 and 33

Greater than 0.9

volts AC at one

tire revolution

per second

Check for damaged tone wheel, incorrect sensor
adjustment, excessive tone wheel runnout
(> .041"), excessive geared hub input bearing play
and tire size mismatch. Repair or replace as neces-
sary.

6-0

Short circuit
between two
solenoid valve
leads of right
front inlet

sole-

noid valve.

6 and 4, 5, 7,

21, 22, 23, 24

5.0-7.5

W

Check electrical resistance of affected valves and
wiring at ECU connector and at modulator assem-
bly plug. Repair or replace wiring as necessary
and replace modulator if short is internal.
Note: Fault code for both affected valves will
be stored in memory.

6-1

Short circuit
between two
solenoid valve
leads of right
front outlet
solenoid valve.

7 and 4, 5, 6,

21, 22, 23, 24

3.0-5.0

W

Check electrical resistance of affected valves and
wiring at ECU connector and at modulator assem-
bly plug. Repair or replace wiring as necessary
and replace modulator if short is internal.
Note: Fault code for both affected valves will
be stored in memory.

6-2

Short circuit
between two
solenoid valve
leads of left
front inlet

sole-

noid valve.

23 and 4, 5, 6,

7, 21, 22, 24

5.0-7.5

W

Check electrical resistance of affected valves and
wiring at ECU connector and at modulator assem-
bly plug. Repair or replace wiring as necessary
and replace modulator if short is internal.
Note: Fault code for both affected valves will
be stored in memory.

6-3

Short circuit
between two
solenoid valve
leads of right
front outlet
solenoid valve.

24 and 4, 5, 6,

7, 21, 22, 23

3.0-5.0

W

Check electrical resistance of affected valves and
wiring at ECU connector and at modulator assem-
bly plug. Repair or replace wiring as necessary
and replace modulator if short is internal.
Note: Fault code for both affected valves will
be stored in memory.

6-4

Short circuit
between two
solenoid valve
leads of right
rear inlet

sole-

noid valve.

4 and 5, 6, 7,

21, 22, 23, 24

5.0-7.5

W

Check electrical resistance of affected valves and
wiring at ECU connector and at modulator assem-
bly plug. Repair or replace wiring as necessary
and replace modulator if short is internal.
Note: Fault code for both affected valves will
be stored in memory.

6-5

Short circuit
between two
solenoid valve
leads of right
rear outlet
solenoid valve.

5 and 4, 6, 7,

21, 22, 23, 24

3.0-5.0

W

Check electrical resistance of affected valves and
wiring at ECU connector and at modulator assem-
bly plug. Repair or replace wiring as necessary
and replace modulator if short is internal.
Note: Fault code for both affected valves will
be stored in memory.

Fault Code List

Ignition key “OFF” to test system (except where noted)

Fault Code

Problem Area

Test Pin

Locations

Values

Check/Repair

7-42

Brake System

_____________________________________________________________

®

6-6

Short circuit
between two
solenoid valve
leads of left
rear inlet

sole-

noid valve.

21 and 4, 5, 6,

7, 22, 23, 24

5.0-7.5

W

Check electrical resistance of affected valves and
wiring at ECU connector and at modulator assem-
bly plug. Repair or replace wiring as necessary
and replace modulator if short is internal.
Note: Fault code for both affected valves will
be stored in memory.

6-7

Short circuit
between two
solenoid valve
leads of left
rear outlet
solenoid valve.

22 and 4, 5, 6,

7, 21, 23, 24

3.0-5.0

W

Check electrical resistance of affected valves and
wiring at ECU connector and at modulator assem-
bly plug. Repair or replace wiring as necessary
and replace modulator if short is internal.
Note: Fault code for both affected valves will
be stored in memory.

6-8

Short circuit
between sole-
noid valve and
RCP relay 1.

11 and 4, 5, 6,

7, 21, 22, 23, 24

Open circuit

Check wiring harness at ECU connector to pump
relay. Repair or replace as necessary.

6-9

Short circuit
between sole-
noid valve and
RCP relay 2.

12 and 4, 5, 6,

7, 21, 22, 23, 24

Open circuit

Check wiring harness at ECU connector to pump
relay. Repair or replace as necessary.

6-12

Right front

wheel speed
signal missing.

17 and 34

Greater than 0.9

volts AC at one

tire revolution

per second.

Check for damaged tone wheel, incorrect sensor
adjustment, excessive tone wheel runnout
(> .041"), excessive geared hub input bearing play
and tire size mismatch. Repair or replace as neces-
sary.

6-13

Left rear

wheel

speed signal
missing.

18 and 35

Greater than 0.9

volts AC at one

tire revolution

per second.

Check for damaged tone wheel, incorrect sensor
adjustment, excessive tone wheel runnout
(> .041"), excessive geared hub input bearing play
and tire size mismatch. Repair or replace as neces-
sary.

6-14

Left front

wheel speed
signal missing.

15 and 32

Greater than 0.9

volts AC at one

tire revolution

per second.

Check for damaged tone wheel, incorrect sensor
adjustment, excessive tone wheel runnout
(> .041"), excessive geared hub input bearing play
and tire size mismatch. Repair or replace as neces-
sary.

6-15

Right rear

wheel speed
signal missing.

16 and 33

Greater than 0.9

volts AC at one

tire revolution

per second.

Check for damaged tone wheel, incorrect sensor
adjustment, excessive tone wheel runnout
(> .041"), excessive geared hub input bearing play
and tire size mismatch. Repair or replace as neces-
sary.

Fault Code List

Ignition key “OFF” to test system (except where noted)

Fault Code

Problem Area

Test Pin

Locations

Values

Check/Repair