DTC P0108 Manifold Absolute Pressure
(MAP) Sensor Circuit High Voltage
The Manifold Absolute
Pressure (MAP) sensor is mounted to the rear of the intake manifold. The MAP
sensor measures the pressure changes within the intake manifold which is an
indication of the engine load. The MAP sensor has a 5.0 volt reference, a
ground, and a signal circuit.
The MAP sensor contains
a diaphragm which changes the resistance based on pressure. When the manifold
pressure is low (high vacuum) the sensor output voltage is low. When the
manifold pressure is high (low vacuum) the sensor output voltage is high.
The MAP sensor voltage
(depending on altitude) can range from 1.0-1.5 volts at idle (high vacuum)
to 4.0 - 4.9 volts at wide open throttle (low vacuum).
When
the PCM senses a signal voltage higher than the normal operating range of the
sensor, this DTC sets.
Conditions
for Running the DTC
- No TP sensor DTCs set.
- The engine is operating.
- The TP sensor angle is less than 5%
when the engine speed is no more than 1,000 RPM. OR
- The TP sensor angle is less than 18%
when engine speed is greater than 1,000 RPM.
Conditions
for Setting the DTC
- The MAP sensor voltage is greater
than 4.3 volts.
- All conditions met for greater than
4 seconds.
Action
Taken When the DTC Sets
- The PCM illuminates the malfunction
indicator lamp (MIL) on the second consecutive ignition cycle that the
diagnostic runs and fails.
- The PCM records the operating
conditions at the time the diagnostic fails. The first time the diagnostic
fails, the PCM stores this information in the Failure Records. If the
diagnostic reports a failure on the second consecutive ignition cycle, the
PCM records the operating conditions at the time of the failure. The PCM
writes the conditions to the Freeze Frame and updates the Failure Records.
Conditions
for Clearing the MIL/DTC
- The PCM turns OFF the malfunction
indicator lamp (MIL) after 3 consecutive ignition cycles that the
diagnostic runs and does not fail.
- A last test failed, or current DTC,
clears when the diagnostic runs and does not fail.
- A history DTC clears after
40 consecutive warm-up cycles, if no failures are reported by this or
any other emission related diagnostic.
- Use a scan tool in order to clear
the MIL and the DTC.
- The following may cause an
intermittent:
- Mis-routed harness
- Rubbed through wire insulation
- Broken wire inside the insulation
- The PCM 5.0 volt reference circuits
are internally connected within the PCM. If all the MAP sensor circuits
are OK, inspect the following component/circuits for malfunctions:
- A/C Refrigerant Pressure sensor
- EGR Valve
- For an intermittent, refer to Symptoms
.
The numbers below refer
to the step numbers on the diagnostic table.
- Using the Freeze
Frame and/or Failure Records data may aid in locating an intermittent
condition. If you cannot duplicate the DTC, the information included in
the Freeze Frame and/or Failure Records data can help determine how many
miles since the DTC set. The Fail Counter and Pass Counter can also help
determine how many ignition cycles the diagnostic reported a pass and/or a
fail. Operate the vehicle within the same freeze frame conditions (RPM,
load, vehicle speed, temperature etc.) that you observed. This will
isolate when the DTC failed. For any test that requires probing the PCM or
component harness connectors, use the Connector Test Adapter Kit J 35616-A .
Using this kit prevents any damage to the harness connector terminals.
- This step verifies
whether a ground circuit is available at the MAP sensor. For any test that
requires probing the PCM or component harness connectors, use the
Connector Test Adapter Kit J 35616-A .
Using this kit will prevent any damage to the harness connector terminals.
|
Step |
Action |
Value(s) |
Yes |
No |
|
Did
you perform the Powertrain On-Board Diagnostic
(OBD) System Check? |
-- |
|||
Did
DTC P1635 fail this ignition cycle? |
-- |
|||
|
Important If the engine idle is
rough, unstable or incorrect, repair the idle condition before using this
table; refer to Symptoms
. Monitor
the MAP sensor voltage on the Engine 1 Data List on the scan tool. Is the MAP
sensor voltage above the specified value? |
4.3V |
|||
Does
the scan tool indicate that this diagnostic failed this ignition? |
-- |
Go to Diagnostic Aids |
||
Is
the MAP sensor voltage below the specified value? |
1.0V |
|||
|
Probe
the sensor ground circuit with the test lamp J 34142-B to
B+. Is the test lamp illuminated? |
-- |
|||
Is
the MAP sensor signal circuit shorted? |
-- |
|||
|
Measure
the voltage at the 5.0 volt reference circuit to the battery ground using the
DMM J 39200
. Is the voltage near the specified value? |
5.0V |
|||
|
Inspect
for a plugged or leaking vacuum supply to the MAP sensor. Is the vacuum
supply OK? |
-- |
|||
Did
you find and correct the condition? |
-- |
|||
Did
you find and correct the condition? |
5 ohms |
|||
|
Important: Program the replacement
PCM. Refer to PCM
Replacement/Programming . Replace
the PCM. Is the action complete? |
-- |
-- |
||
|
Replace
the MAP sensor. Refer to MAP
Sensor Replacement . Is the action complete? |
-- |
-- |
||
|
Repair
the faulty vacuum supply. Is the action complete? |
-- |
-- |
||
|
Repair
the 5.0 volt reference circuit for a short to voltage. Refer to Wiring
Repairs in Wiring Systems. Is the action complete? |
-- |
-- |
||
Does
the scan tool indicate that this test ran and passed? |
-- |
|||
|
Select
the Capture Info option and the Review Info option using the scan tool. Does
the scan tool display any DTCs that you have not diagnosed? |
-- |
Go to the applicable
DTC table |
System OK |