MAZDA MIATA 1991 Factory Service Manual

Fig. 9: Checking Back-Up Battery Connector (RX7)
Courtesy of MAZDA MOTORS CORP.

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AIR BAG RESTRAINT SYSTEM MAZDA 1990-91 AIR BAGS
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Fig. 10: Locating Diagnostic Module Black & Gray Connectors (Miata)
Courtesy of MAZDA MOTORS CORP.

1991 Mazda MX-5 Miata
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Fig. 11: Locating Diagnostic Module Black & Gray Connectors (RX7)
Courtesy of MAZDA MOTORS CORP.
DIAGNOSTIC TEST NO. 3
Warning Light Flashes 5 Or 9 Times
1. Disable air bag system. See DISABLING & ACTIVATING AIR BAG SYSTEM. Disconnect front
impact sensor connectors (center, left, and right), and measure resistance of each sensor. See Fig. 12
.
Resistance should be approximately 1.2 k/ohms. If resistance is not as specified, replace sensor.
2. If resistance is about 1.2 k/ohms, reconnect all front impact sensor connectors. Disconnect diagnostic
module Black and Gray connectors. See Fig. 10
or Fig. 11 . Measure resistance between diagnostic
module Gray connector Brown/Green wire and ground. If resistance is 1.2 k/ohms, go to next step. If
resistance is not 1.2 k/ohms, replace wire harness.
3. Measure resistance between diagnostic module Gray connector Brown/Red wire and ground. If resistance
is 1.2 k/ohms, go to next step. If resistance is not 1.2 k/ohms, replace wire harness.
4. Measure resistance between diagnostic module Black connector Brown/Black wire and ground. If
resistance is 1.2 k/ohms, replace dia
gnostic module. If resistance is not 1.2 k/ohms, replace wire harness.

1991 Mazda MX-5 Miata
AIR BAG RESTRAINT SYSTEM MAZDA 1990-91 AIR BAGS
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Fig. 12: Checking Impact Sensor Resistance
Courtesy of MAZDA MOTORS CORP.
DIAGNOSTIC TEST NO. 4
Warning Light Flashes 10 Times
1. Disable air bag system. See DISABLING & ACTIVATING AIR BAG SYSTEM. Disconnect front
impact sensor connectors (center, left, and right), and measure resistance of each sensor. See Fig. 12
.
Resistance should be approximately 1.2 k/ohms. If resistance is not as specified, replace sensor and go to
step 5).
2. If resistance is about 1.2 k/ohms, reconnect all front impact sensor connectors. Disconnect diagnostic
module Black and Gray connectors. See Fig. 10
or Fig. 11 . Measure resistance between diagnostic
module Gray connector Brown/Green wire and ground. If resistance is 1.2 k/ohms, go to next step. If
resistance is not 1.2 k/ohms, replace wire harness.
3. Measure resistance between diagnostic module Gray connector Brown/Red wire and ground. If resistance
is 1.2 k/ohms, go to next step. If resistance is not 1.2 k/ohms, replace wire harness.
4. Measure resistance between diagnostic module Black connector Brown/Black wire and ground. If
resistance is 1.2 k/ohms, go to next step. If resistance is not 1.2 k/ohms, replace wire harness and go to
next step.
5. If disconnected, reconnect dia
gnostic module and clockspring connectors. Reconnect negative battery

1991 Mazda MX-5 Miata
AIR BAG RESTRAINT SYSTEM MAZDA 1990-91 AIR BAGS
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cable. Turn ignition switch to ON position and check warning light operation. If warning light flashes 10
times, replace diagnostic module.
DIAGNOSTIC TEST NO. 5
Warning Light Flashes 4 Times
1. Disable air bag system. See DISABLING & ACTIVATING AIR BAG SYSTEM. Disconnect diagnostic
module Black and Gray connectors. See Fig. 10
or Fig. 11 . Check continuity between Black connector
Green/White wire terminals. If continuity is not present, replace wire harness.
2. If continuity is present, check continuity between Black connector Green wire and ground (1990 Miata),
or between Gray connector Red/Black wire terminal and ground (all others). If continuity is not present,
go to step 4). If continuity is present, check continuity between Black connector Green wire terminal and
Gray connector Green/Black wire terminal. If continuity is present, go to step 4) (1990 Miata), or step 5)
(all others).
3. If continuity is not present, disconnect rear safing sensor connectors. Check continuity between sensor
terminals "B" and "E". See Fig. 13
. If continuity is present, replace wire harness. If continuity is not
present, replace rear safing sensor.
4. Check rear safing sensor installation; repair as necessary. If installation is okay, disconnect rear safing
sensor connectors. Check continuity between sensor terminal "A" and ground. If continuity is not present,
replace rear safing sensor. If continuity is present, replace wire harness.
5. Disconnect diagnostic connector. Check continuity between Black connector Green/White wire and
ground. If continuity is present, replace wire harness. If continuity is not present, repeat step 4).

1991 Mazda MX-5 Miata
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Fig. 13: Identifying Rear Safing Sensor Terminals
Courtesy of MAZDA MOTORS CORP.
DIAGNOSTIC TEST NO. 6
Warning Light Flashes 6 Times
1. Disconnect negative battery cable. Check connection of Orange/Blue clockspring connector; repair as
necessary.
2. If connection is okay, disconnect air bag module and clockspring connector. Check continuity, as shown
in illustration, for both terminals of Blue side of clockspring connector. See Fig. 14
. If continuity is not
present, replace Oran
ge/Blue clockspring connector.

1991 Mazda MX-5 Miata
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Fig. 14: Checking Resistance at Clockspring Terminal
Courtesy of MAZDA MOTORS CORP.
3. If continuity is present, disconnect diagnostic module Black and Gray connectors. See Fig. 10
or Fig. 11.
Check continuity between diagnostic module Black connector Green/White wire and clockspring
connector Red wire. Also check continuity between diagnostic module Black connector Green/Yellow
wire and clockspring connector Green/Yellow wire. If continuity is not present, replace wire harness
assembly.
4. If continuity is present, check continuity between diagnostic module Black connector Green/Yellow wire
and ground. If continuity is present, replace wire harness assembly. If continuity is not present, replace air
bag module.
DIAGNOSTIC TEST NO. 7
Warning Light Flashes 2 Or 8 Times
1. Disable air bag system. See DISABLING & ACTIVATING AIR BAG SYSTEM. Disconnect diagnostic
module Black and Gray connectors. See Fig. 10
or Fig. 11 . Check continuity between Black connector
Brown/Yellow wire and ground. If continuity is not present, go to step 4). If continuity is present, go to
next step.

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2. Check continuity between Black connector Brown/White wire and ground. If continuity is not present, go
to step 5). If continuity is present, go to next step.
3. Check continuity between Black connector Brown wire and ground. If continuity is present, replace
diagnostic module. If continuity is not present, go to step 6).
4. Disconnect right front impact sensor connector. Check continuity between ground and each harness
sensor terminal. See Fig. 15
. If continuity is present, replace wire harness assembly. If continuity is not
present, go to step 7).
Fig. 15: Checking Continuity at Right Front Impact Sensor Connector

Courtesy of MAZDA MOTORS CORP.
5. Disconnect center front impact sensor connector. Check continuity between ground and each harness
sensor terminal. If continuity is present, replace wire harness assembly. If continuity is not present, go to
step 7).
6. Disconnect left front impact sensor connector. Check continuity between ground and each harness sensor
terminal. If continuity is present, replace wire harness assembly. If continuity is not present, go to step 7).
7. Ensure all front impact sensors are correctly installed. If all front impact sensors are installed correctly,
replace defective front impact sensor.
DIAGNOSTIC TEST NO. 8

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AIR BAG RESTRAINT SYSTEM MAZDA 1990-91 AIR BAGS
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Warning Light Flashes 7 Times
1. Disable air bag system. See DISABLING & ACTIVATING AIR BAG SYSTEM. Disconnect diagnostic
module Black and Gray connectors. See Fig. 10
or Fig. 11 .
2. Check continuity between Black connector Black wire and ground. If continuity is present, replace
diagnostic module. If continuity is not present, replace wire harness.
WIRING DIAGRAMS
Fig. 16: Air Bag System Wiring Diagram (1990 Miata)
Courtesy of MAZDA MOTORS CORP.

1991 Mazda MX-5 Miata
AIR BAG RESTRAINT SYSTEM MAZDA 1990-91 AIR BAGS
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Fig. 17: Air Bag System Wiring Diagram (1990 RX7)
Courtesy of MAZDA MOTORS CORP.

1991 Mazda MX-5 Miata
AIR BAG RESTRAINT SYSTEM MAZDA 1990-91 AIR BAGS
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