SsangYong Musso. Manual - part 127

1F-92 ENGINE CONTROLS

SSANGYONG Y158

System Description

The Engine Control Module (ECM) uses the Manifold
Absolute Pressure (MAP) sensor to control the fuel
delivery and the ignition timing. The MAP sensor
measures the changes in the intake manifold pressure
which results from engine load (intake manifold vacuum)
and the rpm changes, and it converts these into voltage
outputs.

The ECM can detect if the MAP sensor is not responding
to the Throttle Position (TP) changes by comparing the
actual MAP change to a predicted MAP change based
on the amount of TP change that occurs and engine
speed. If the ECM does not see the expected MAP
change or more, DTC P0105 will set.

Conditions for Setting the DTC

•••••

The ratio between measured intake manifold pressure
and emergency intake manifold pressure is between
0.5 and 1.5 for more than 2.5 seconds.

•••••

DTCs P0107, P0108, P0120, P0335, P0336 and
P0601 are not set.

•••••

Misfire is not detected.

•••••

Start end detected.

•••••

Engine speed gradient is less than 200 [rpm/s].

•••••

Throttle valve gradient is less than 20 [°/s].

•••••

Throttle valve angle is greater than 15°.

Action Taken When the DTC Sets

•••••

The Malfunction Indicator Lamp (MIL) will illuminate
after two consecutive driving cycles in which the diag-
nostic runs with the fault active.

•••••

The ECM will record operating conditions at the time
the diagnostic fails. This information will be stored in
the Freeze Frame and Failure Records buffers.

•••••

A history DTC is stored.

Conditions for Clearing the MIL/DTC

•••••

The Malfunction Indicator Lamp (MIL) will turn off af-
ter three consecutive driving cycles in which the diag-
nostic runs without a fault.

•••••

A history DTC will clear after 40 consecutive warm-
up cycles without a fault.

•••••

The DTC(s) can be cleared by using the scan tool.

Diagnostic Aids

With the ignition ON and the engine stopped, the manifold
pressure is equal to atmospheric pressure and the signal

DIAGNOSTIC TROUBLE CODE (DTC) P0105

MANIFOLD ABSOLUTE PRESSURE PLAUSIBILITY (2.3L DOHC)

voltage will be high. This information is used by the ECM
as an indication of vehicle altitude. Comparison of this
reading with a known good vehicle with the same sensor
is a good way to check the accuracy of a suspect sensor.
Readings should be the same ±0.4 volts.

The Map sensor vacuum source should be thoroughly
checked for restrictions at the intake manifold.

Test Description

Numbers below refer to the step numbers on the
Diagnostic Table.

1. The Euro On-Board Diagnostic (EOBD) System

Check prompts the technician to complete some
basic checks and store the freeze frame and failure
records data on the scan tool if applicable. This
creates an electronic copy of the data taken when
the malfunction occurred. The information is then
stored on the scan tool for later reference.

2. A sensor that displays an ignition ON, engine OFF

BARO value that does not appear the same as a
known good vehicle should be considered to be
malfunctioning.

3. While starting the engine, the MAP sensor should

detect any changes in the manifold pressure. This
test is to determine if the sensor is stuck at a value.

4. A normal MAP sensor will react as quickly to the

throttle changes as they can be made. A sensor
should not appear to be lazy or catch up with the
throttle movements.

5. This step checks if the reason for no MAP change

was due to a faulty sensor or vacuum source to the
sensor.

7. The MAP sensor vacuum source should be

thoroughly checked for restrictions. A drill bit can
be used to clean out any casting flash that may
exist in the vacuum port.

9. The MAP Sensor System Performance diagnostic

may have to complete several tests before
determining if the diagnostic has passed or failed
the last test. Operate the vehicle in the Conditions
for Setting the DTC several times to ensure that the
diagnostic runs enough tests to pass or fail.

10. If no faults have been found at this point and no

additional DTCs are set, refer to “Diagnostic Aids”
in this section for additional checks and information.

ENGINE CONTROLS 1F-93

SSANGYONG Y158

Perform an Euro On-Board Diagnostic (EOBD) System
Check.
Is the system check complete?

1. Install a scan tool.
2. Turn the ignition switch ON with the engine not

running.

3. Compare the Barometric Pressure (BARO) reading

with a known good vehicle.

Is the BARO reading similar?
Start the engine while watching the Manifold Absolute
Pressure (MAP) sensor value.
Does the MAP sensor value change while starting the
engine?
With the engine still running, snap the throttle while
watching the MAP sensor display in the scan tool.
Does the MAP sensor value change rapidly with the
throttle position changes?
1. Turn the ignition switch OFF.
2. Remove the MAP sensor and install a vacuum pump

to the MAP sensor.

3. Turn the ignition switch ON, with the engine OFF.
4. Apply 15 in Hg to the MAP sensor.
Does the MAP sensor value on the scan tool change?
1. Remove the MAP sensor from the manifold port.
2. Inspect the port and MAP sensor for restrictions and

repair as necessary.

Is the repair complete?
Repair the restriction in the MAP sensor vacuum port as
necessary.
Is the repair complete?
Replace the MAP sensor.
Is the repair complete?
1. Using the scan tool, clear the Diagnostic Trouble

Codes (DTCs).

2. Start the engine and idle at normal operating

temperature.

3. Operate the vehicle within the Conditions for setting

this DTC as specified in the supporting text.

Does the scan tool indicate that this diagnostic has run
and passed?
Check if any additional DTCs are set.
Are any DTCs displayed that have not been diagnosed?

Step

Action

Value(s)

Yes

Go to Step 2

Go to “Euro

On-Board

Diagnostic

System Check”

DTC P0105 Manifold Absolute Pressure Rationality (2.3L DOHC)

Go to Step 3

Go to Step 8

Go to Step 4

Go to Step 5

Go to Step 9

Go to Step 6

Go to Step 7

Go to Step 8

Go to Step 9

Go to Step 8

Go to Step 9

Go to Step 10

Go to Step 2

Go to

applicable

DTC table

System OK

1F-94 ENGINE CONTROLS

SSANGYONG Y158

Circuit Description

The ECM sends a 5 volt reference voltage to the MAP
sensor. As the manifold pressure changes, the output
voltage of the MAP sensor also changes. By monitoring
the MAP Sensor output voltage, the ECM knows the
manifold pressure. A low pressure (low voltage) output
voltage will be about 1.0 to 1.5 volts at idle, while higher
pressure (high voltage) output voltage will be about 4.5
to 4.8 volts at Wide Open Throttle (WOT). The MAP
sensor is also used, under certain conditions, to
measure Barometric Pressure (BARO), allowing the
ECM to make adjustments for different altitudes.

Conditions for Setting the DTC

•••••

MAP sensor voltage is less than 0.1 volt

•••••

No fault of engine speed.

•••••

Engine start end reached.

DIAGNOSTIC TROUBLE CODE (DTC) P0107

MANIFOLD ABSOLUTE PRESSURE LOW VOLTAGE (2.3L DOHC)

Action Taken When the DTC Sets

•••••

The Malfunction Indicator Lamp (MIL) will illuminate
after two consecutive driving cycles in which the diag-
nostic runs with the fault active.

•••••

The ECM will record operating conditions at the time
the diagnostic fails. This information will be stored in
the Freeze Frame and Failure Records buffers.

•••••

A history DTC is stored.

Conditions for Clearing the MIL/DTC

•••••

The Malfunction Indicator Lamp (MIL) will turn off af-
ter three consecutive driving cycles in which the diag-
nostic runs without a fault.

•••••

A history DTC will clear after 40 consecutive warm-
up cycles without a fault.

•••••

The DTC(s) can be cleared by using the scan tool.

Diagnostic Aids

With the ignition ON and the engine stopped, the manifold
pressure is equal to atmospheric pressure and the signal
voltage will be high. This information is used by the ECM
as an indication of vehicle altitude. Comparison of this
reading with a known good vehicle with the same sensor
is a good way to check the accuracy of a suspect sensor.
Readings should be the same ± 0.4 volts.

YAB1F110

ENGINE CONTROLS 1F-95

SSANGYONG Y158

Test Description

Numbers below refer to the step numbers on the
Diagnostic Table.

1. The Euro On-Board Diagnostic (EOBD) System

2. This step will determine if DTC P0107 is the result

of a hard failure or an intermittent condition.

3. Jumpering harness terminal 2 to 3 (signal circuit to

5 volts) will determine if the sensor is malfunctioning
or if there is a problem with the ECM or wiring.

6. The scan tool may not display 104kPa. The

important thing is that the ECM recognizes the
vacuum as more than 90kPa, indicating that the
ECM and the signal circuit are OK. A test light that
illuminates indicates a short to ground in the signal
circuit.

7. A short to ground in the 5 volt reference circuit could

also set additional DTCs.

11. The replacement ECM must be reprogrammed.

Refer to the latest Techline procedure for the ECM
reprogramming.

Perform an Euro On-Board Diagnostic (EOBD) System
Check.
Is the system check complete?

1. Connect scan tool and start the engine.
2. With engine idling, read the Manifold Absolute

Pressure (MAP).

Does the scan tool display a MAP below the specified
value?
1. Turn the ignition switch OFF.
2. Disconnect the MAP sensor electrical connector.
3. Jumper the MAP signal circuit at terminal 2 to the 5

volt reference circuit at terminal 3.

4. Turn the ignition switch ON.
Does the MAP read more than the specified value?
1. Turn the ignition switch ON with the engine OFF,

review the Freeze Frame data, and note the
parameters.

2. Operate the vehicle within the frieze frame conditions

and Conditions For setting the DTC as noted.

Does the scan tool display MAP below the specified
value?
Inspect the MAP sensor harness electrical connector
terminals for the following conditions:

•••••

Poor connections.

•••••

Proper contact tension.

•••••

Poor terminal to wire connection.

Is a problem found?
1. Turn the ignition switch OFF.
2. Remove the jumper wire.
3. Probe the MAP sensor signal circuit terminal 2 with

a test light to B+.

4. Turn the ignition switch ON.
Does the scan tool read over the specified value?

Step

Action

Value(s)

Yes

12 kPa

Go to Step 3

Go to Step 4

Go to Step 2

Go to “Euro

On-Board

Diagnostic

System Check”

96 kPa

Go to Step 5

Go to Step 6

12 kPa

Go to Step 3

Go to

"Diagnostic

Aids"

Go to Step 8

Go to Step 9

DTC P0107 Manifold Absolute Pressure Low Voltage (2.3L DOHC)

90 kPa

Go to Step 7

Go to Step 12

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