2003 FORD MUSTANG check engine

DESCRIPTION AND OPERATION
Instrument Cluster
The instrument cluster (10849) consists of the following components:
Instrument Cluster—
Base 3.8L Engine
SECTION 413-
01: Instrument Cluster 2003 Mustang Workshop Manual Item Part
Number Description
1 — Fuel gauge
2 — Engine coolant temperature gauge
3 — Speedometer
4 — Turn signal/hazard indicator
5 — High beam indicator
6 — Tachometer
7 — Odometer
8 — Trip odometer reset button
9 — Voltmeter gauge
10 — Oil pressure gauge
11 — CHECK FUEL CAP indicator
12 — BRAKE warning indicator
13 — ABS warning indicator
14 — Traction control indicator
15 — Overdrive off (O/D OFF) indicator (automatic Klj . 1 ba
42003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_5108/S3B~us~en~ ...

Instrument Cluster—
Base 4.6L Engine transmission)
16 — LOW FUEL level indicator
17 — SERVICE ENGINE SOON indicator
18 — THEFT indicator
19 — AIR BAG warning indicator
20 — Charging system indicator
21 — Safety belt warning indicator
Item Part
Number Description
1 — Fuel gauge
2 — Engine coolant temperature gauge
3 — Speedometer
4 — Turn signal/hazard indicator
5 — High beam indicator
6 — Tachometer
7 — Odometer
8 — Trip odometer reset button
9 — Voltmeter gauge
10 — Oil pressure gauge
11 — CHECK FUEL CAP indicator
12 — BRAKE warning indicator
13 — ABS warning indicator Klj . 2 ba
42003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_5108/S3B~us~en~ ...

Instrument Cluster—
Cobra 14 — Traction control indicator
15 — Overdrive off (O/D OFF) indicator (automatic
transmission)
16 — LOW FUEL level indicator
17 — SERVICE ENGINE SOON indicator
18 — THEFT indicator
19 — AIR BAG warning indicator
20 — Charging system indicator
21 — Safety belt warning indicator
Item Part
Number Description
1 — Fuel gauge
2 — Engine coolant temperature gauge
3 — Speedometer
4 — Turn signal/hazard indicator
5 — High beam indicator
6 — Tachometer
7 — Odometer
8 — Trip odometer reset button
9 — Boost gauge
10 — Oil pressure gauge
11 — CHECK FUEL CAP indicator
12 — BRAKE warning indicator Klj . 3 ba
42003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_5108/S3B~us~en~ ...

The boost pressure gauge on the instrument cluster receives and measures the boost pressure
directly from the intake manifold. The boost pressure gauge will display between 0.0-
0.48 kpa (0.0-10
psi) boost pressure dependent upon accelerator position, engine load, and engine rpm.
LOW FUEL Level Indicator
The low fuel level indicator is hardwired from the fuel sender to the instrument cluster. The instrument
cluster will illuminate the low fuel indicator when the usable fuel quantity is less than 1/8 tank (15%) of
fuel tank capacity.
Oil Pressure Gauge
The oil pressure gauge is hardwired from the oil pressure switch to the instrument cluster. The oil
pressure gauge will indicate either normal or no oil pressure.
CHECK FUEL CAP
The CHECK FUEL CAP indicator is used to indicate significant leaks in the fuel tank evaporative
system due to a loose fuel cap. Fuel tank pressure is monitored by the PCM. If a leak is detected the
PCM signals a fault to the instrument cluster via the SCP network. Once the PCM has detected a
loose fuel cap and the CHECK FUEL CAP indicator is illuminated, the indicator will remain illuminated
until the fuel cap is secured and the vehicle has been running for several minutes. For additional
information, refer to the Powertrain Control/Emissions Diagnosis (PC/ED) manual.
BRAKE Warning Indicator
The BRAKE warning indicator activates when the generic electronic module (GEM) detects the ignition
switch circuits are in the RUN state, when the GEM detects low brake fluid level, or that the parking
brake is applied. The BRAKE warning indicator will prove out starting when the GEM detects that the
ignition circuits have made a transition to RUN or START from OFF, ACC, or keyout and ending when
either three seconds have elapsed or when the GEM detects the ignition circuits have made a
transition to OFF, ACC, or keyout.
Safety Belt Warning Indicator
The safety belt switch is hardwired to the GEM. The safety belt warning indicator will be illuminated
when the GEM sends a ground signal to the instrument cluster.
ABS Warning Indicator
The ABS warning indicator will be illuminated when the anti- lock brake control module sends a ground
signal to the instrument cluster. The prove- out of the ABS indicator is controlled by the anti- lock brake
control module.
SERVICE ENGINE SOON Indicator
The SERVICE ENGINE SOON indicator receives its signal from the PCM over the SCP network. If the
instrument cluster does not receive a message from the PCM within five seconds, the instrument
cluster will illuminate the SERVICE ENGINE SOON indicator and log a diagnostic trouble code (DTC).
High Beam Indicator
The high beam indicator will illuminate when the steering column multifunction switch is in the high
beam position by sending a battery signal to the instrument cluster. Right and Left Turn Indicator Klj . 3 ba
412003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_5108/S3B~us~en~ ...

3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible)
before proceeding to the next step.
4. If the concern remains after the inspection, connect the diagnostic tool to the data link connector (DLC) located beneath the instrument panel and select the vehicle to be tested from the
diagnostic tool menu. If the diagnostic tool does not communicate with the vehicle:
zcheck that the program card is correctly installed.
z check the connections to the vehicle.
z check the ignition switch position.
5. If the diagnostic tool still does not power up, refer to the diagnostic tool operating manual.
6. Carry out the DATA LINK DIAGNOSTICS test. If the diagnostic tool responds with: zCKT914, CKT915 OR CKT70 = ALL ECUS NO RESP/NOT EQUIP, refer to Section 418 -
00 .
z NO RESP/NOT EQUIP for the instrument cluster, Go To Pinpoint Test A or for the
generic electronic module (GEM), Go To Pinpoint Test W .
z SYSTEM PASSED, retrieve and record the continuous diagnostic trouble codes (DTCs),
erase the continuous DTCs and carry out the self- test diagnostics for the instrument
cluster or the GEM.
7. If the DTCs retrieved are related to the concern, go to the Instrument Cluster Diagnostic Trouble Code (DTC) Index or the GEM Diagnostic Trouble Code Index to continue diagnostics.
8. If no DTCs related to the concern are retrieved, proceed to the Symptom Chart to continue diagnostics.
Instrument Cluster Self- Diagnostic Mode
To enter the instrument cluster self- diagnostic mode, press and hold the instrument cluster
SELECT/RESET button, turn the ignition switch to the RUN position, and then continue pressing the
SELECT/RESET button (five seconds) until tESt is displayed in the odometer. The SELECT/RESET
button must be released within three seconds of the odometer tESt display to begin the self- diagnostic
mode. Press the SELECT/RESET button to advance through the following steps until dtc is displayed.
Depressing the SELECT/RESET button will display any stored continuous DTCs before proceeding to
the next step. z
Engine coolant level
z Accessory drive belt
z Engine oil level
z Parking brake position switch
z Brake fluid level
z Boost gauge pressure line „
5 (15A)
„ 7 (15A)
„ 11 (15A)
„ 13 (15A)
„ 21 (5A)
„ 23 (15A)
„ 24 (30A)
„ 29 (15A)
„ 30 (15A)
„ 32 (15A)
„ 34 (20A)
„ 35 (15A)
„ 37 (5A)
„ 38 (20A)
„ 39 (5A)
z Circuitry Klj . 5 ba
412003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_5108/S3B~us~en~ ...

Odometer
Display Description
GAGE Activates gauge sweep of all gauges, then displays present gauge values. Also
carries out the checksum tests on ROM and EE. All segments
illuminated Illuminates all odometer segments.
bulb Illuminates all micro-controlled indicators and LEDs. Install a new indicator or LED as
necessary. r Returns to normal operation of all micro-
controlled indicators and LEDs and displays
hexadecimal value for ROM level (used when requesting assistance from the hotline). EE Displays hexadecimal value for EE level (used when requesting assistance from the
hotline). dt Displays hexadecimal coding of final manufacturing test date (used when requesting
assistance from the hotline). dtc Displays continuous DTCs in hexadecimal format. Pressing the SELECT/RESET
button will display any DTCs stored before proceeding to the next step. enG Displays the English speed in mph. Speedometer will indicate present speed within
tolerances. Display will show 0 if input is not received, if input received is invalid for one second or more, or if speed is 0. m Displays the metric speed data (km/h). Speedometer will indicate present speed
within tolerances. Display will show 0 if input is not received, if input received is invalid for one second or more, or if speed is 0. tAc Displays the tachometer data received from the PCM via the SCP network within
tolerances. Tachometer will indicate present rpm. Display will show 0 if input is not received, if input received is invalid for one second or more, or if engine rpm is 0. FUEL Displays the code (0-255) for the fuel sender input to the instrument cluster. The fuel
gauge will display a filtered fuel level value. This filter will keep the pointer from moving suddenly or erratically.
z255 = open send +/- 0
z 232 = full stop +/- 0
z 215 = full mark +/- 10
z 178 = 3/4 mark +/- 8
z 138 = 1/2 mark +/- 7
z 93 = 1/4 mark +/- 5
z 41 = E mark +/- 4
z 54=LOW FUEL (0- 59)
z 0-18=short (0- 20 max) OIL Displays the code (0-
250) for the oil pressure switch input to the instrument cluster.
Oil pressure gauge will indicate present oil pressure. Normal oil pressure (greater
than 6 psi) will display a value between 000 and 176. A low oil pressure or an
inoperative engine oil pressure switch (less than 6 psi) will display a value greater
than 176. dEGC Display of engine temperature in degrees C input from cylinder head temperature
sensor.
z 49 C = "C" mark
z 60 C = normal band start
z 120 C = normal band end
z -40 C = no SCP message for 5 seconds bAtt Displays the code (0-255) for the battery voltage input to the instrument cluster.
Battery voltage gauge will indicate present battery voltage. Klj . 6 ba
412003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_5108/S3B~us~en~ ...

PINPOINT TEST D: INCORRECT TEMPERATURE GAUGE
INDICATION
PINPOINT TEST E: INCORRECT VOLTAGE GAUGE INDICATION—
EXCEPT COBRA z
Check for:
zcorrosion
z pushed- out pins
z Connect all instrument cluster connectors and make sure they
seat correctly.
z Operate the system and verify the concern is still present.
z Is the concern still present? instrument cluster.
REFER to
Instrument Cluster in this section.
TEST the system for
normal operation.
No
The system is
operating correctly at
this time. Concern may
have been caused by a
loose or corroded
connector. CLEAR the
DTCs. REPEAT the
self- test. Test Step Result / Action to Take
D1 CARRY OUT THE INSTRUMENT CLUSTER
ENGINE COOLANT TEMPERATURE GAUGE
ACTIVE COMMAND z
Connect the diagnostic tool.
z Key in ON position.
z Enter the following diagnostic mode on the
diagnostic tool: Instrument Cluster Active
Command.
z Trigger instrument cluster active command
ENGCOOLNT. Monitor the engine coolant
temperature gauge while adjusting the
ENGCOOLNT active command to read 50%
and 100%.
z Does the temperature gauge start at cold,
move to half at 50%, and full hot at 100%? Yes
REFER to the Powertrain
Control/Emissions Diagnosis (PC/ED)
manual.
No
GO to
D2 .
D2 CHECK FOR CORRECT INSTRUMENT
CLUSTER OPERATION z
Disconnect all instrument cluster connectors.
z Check for:
zcorrosion
z pushed- out pins
z Connect all instrument cluster connectors and
make sure they seat correctly.
z Operate the system and verify the concern is
still present.
z Is the concern still present? Yes
INSTALL a new instrument cluster.
REFER to
Instrument Cluster in this
section. TEST the system for normal
operation.
No
The system is operating correctly at this
time. Concern may have been caused by
a loose or corroded connector. CLEAR the
DTCs. REPEAT the self-test. Test Step Result / Action to
Take E1 CHECK THE INSTRUMENT CLUSTER Klj . 19 ba
412003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_5108/S3B~us~en~ ...

PINPOINT TEST P: THE CHARGING SYSTEM WARNING INDICATOR
IS NEVER/ALWAYS ON
Test Step Result / Action to Take
P1 CHECK THE CHARGING SYSTEM
CAUTION: Use the correct probe adapter(s) when
making measurements. Failure to use the correct probe
adapter(s) may damage the connector.
z Check the charging system operation. Refer to Section 414 -
00 .
z Is the charging system operating correctly? Yes
GO to
P2 .
No
REFER to Section 414 - 00 .
P2 CHECK CHARGING SYSTEM WARNING INDICATOR WITH
ENGINE OFF z
Key in ON position.
z Observe the charging system warning indicator.
z Is the charging system warning indicator on? Yes
GO to
P5 .
No
GO to P3 .
P3 CHECK THE INSTRUMENT CLUSTER INPUT
z
Key in OFF position.
z Disconnect: Generator C102c.
z Connect a fused (10A) jumper wire between the generator
C102c pin 1, circuit 904 (LG/RD), harness side and ground.
z Key in ON position.
z Does the charging system indicator illuminate? Yes
INSTALL a new generator.
REFER to
Section 414 - 02 .
TEST the system for normal
operation.
No
GO to P4 .
P4 CHECK CIRCUIT 904 (LG/RD) FOR OPEN
z
Key in OFF position.
z Disconnect: Instrument Cluster C220a .
z Measure the resistance between the instrument cluster
C220a pin 5, circuit 904 (LG/RD), harness side and the
generator C102c pin 1, circuit 904 (LG/RD), harness side.
z Is the resistance less than 5 ohms? Yes
GO to
P7 .
No
REPAIR the circuit. TEST
the system for normal
operation. P5 CHECK THE GENERATOR Klj . 32 ba
412003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_5108/S3B~us~en~ ...