• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance |
---|---|---|---|---|---|
5-Volt Reference | P012C, P0641 | P0069 | P012C | P0641 | P0069, P012B |
SC Inlet Pressure Sensor Signal | P012B, P012C | P0069 | P012C | P0120, P0641, P2229 | P0069, P012B |
Low Reference | -- | P0069, P012B | P012B, P012D | -- | P0069, P012B |
Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance |
---|---|---|---|---|---|
5-Volt Reference Circuit | P0069, P0641, P2228 | P0069 | P0069, P2228 | P0069, P0641, P2229 | P2227 |
BARO Sensor Signal Circuit | P0069, P2228 | P0069 | P0069, P2228 | P0069, P0641, P2224, P2229 | P2227 |
Low Reference Circuit | -- | P0069 | P0069, P2229 | -- | P2227 |
Circuit | Short to Ground | Open | Short to Voltage |
---|---|---|---|
Operating Conditions: Ignition ON, engine OFF Normal Parameter Range: BARO | |||
5-Volt Reference | 8-10 kPa | 8-10 kPa | 96-104 kPa |
SC Inlet Pressure Sensor Signal | 8-10 kPa | 8-10 kPa | 96-104 kPa |
Low Reference | -- | 90-104 kPa | -- |
Circuit | Short to Ground | Open | Short to Voltage |
---|---|---|---|
Operating Conditions: Ignition ON, engine OFF Normal Range: BARO | |||
5-Volt Reference Circuit | 8-10 kPa | 8-10 kPa | 200-208 kPa |
Sensor Signal Circuit | 8-10 kPa | 8-10 kPa | 200-208 kPa |
Low Reference Circuit | -- | 191 kPa | -- |
The barometric pressure (BARO) sensor measures the pressure of the atmosphere. This pressure is affected by altitude and weather conditions. A diaphragm within the BARO sensor is displaced by the pressure changes that occur from varying altitudes and weather conditions. The sensor translates this diaphragm action into the voltage signal input that is used by the engine control module (ECM) for diagnostics and emissions control.
The supercharger inlet absolute pressure (SCIAP) sensor measures the absolute pressure of the air just after the throttle body, at the inlet of the supercharger. The plenum volume between the throttle body (TB) and the supercharger is where this sensor is located, and for the purpose of this diagnostic, this area is considered to be the intake manifold. The diaphragm within the SCIAP sensor functions in the same manner as the BARO sensor. The sensors are not interchangeable.
The purpose of this diagnostic is to analyze the correlation between the BARO sensor, and the SCIAP sensor. This is accomplished by continually comparing the difference between BARO and SCIAP at key ON, engine OFF (KOEO), at closed throttle idle conditions, and at wide open throttle update events. At KOEO the difference between BARO and SCIAP is represented on the scan tool by the SC Inlet Pressure parameter as a value that should be very close to zero. A negative SC Inlet Pressure parameter means that the BARO sensor value is less than the SCIAP value. A positive SC Inlet Pressure parameter represents a BARO sensor value that is more than the SCIAP value.
At idle the SC Inlet Pressure parameter represents the calculated difference between BARO and the reduced pressure that is present in the supercharger intake plenum as a positive value. At wide open throttle the SC Inlet Pressure parameter represents the calculated difference between BARO and the increased pressure that is present in the supercharger intake plenum, and should be very close to zero.
Both sensors have the following types of circuits:
• | A ECM supplied and regulated 5-volt reference circuit |
• | A ECM supplied ground for the low reference circuit |
• | A sensor signal circuit that supplies a voltage input to the ECM |
Changes in BARO due to weather are relatively small, while changes due to altitude are significant. Pressure can range from 56 kPa at an altitude of 4267 meters (14,000 feet), to 104 kPa at or below sea level.
If the ECM detects that the BARO sensor signal and the SCIAP sensor signal are not within a calibrated range of each other, whether that value is negative or positive, DTC P0069 sets.
• | DTCs P0068, P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0128, P012B, P012C, P012D, P0220, P0502, P1516, P2101, P2227, P2228, P2229 are not set. |
• | The ignition is ON. |
OR |
• | The engine is running. |
• | DTC P0069 runs continuously when the above conditions are met. |
• | The ECM detects that during ignition ON, with the engine OFF, the calculated difference between BARO and SCIAP, whether that value is negative or positive, is greater than 12 kPa for greater than 30 seconds. |
OR |
• | The ECM has detected that a wide open throttle update event has occurred within the previous 2 kilometers (1.2 miles) and the difference between BARO, and a calculated BARO using the SCIAP sensor, is greater than 12 kPa for greater than 30 seconds. |
OR |
• | The ECM has not detected a wide open throttle update event within the previous 2 kilometers (1.2 miles) and the difference between BARO, and a calculated BARO using the SCIAP sensor, is greater than 60 kPa for greater than 30 seconds. |
DTC P0069 is a Type B DTC.
DTC P0069 is a Type B DTC.
• | Any condition that can cause the BARO or SCIAP sensors to be shifted in value may cause this DTC to set. |
• | A slight to moderate resistance of 20-50 ohms on the 5-volt reference terminal C or the low reference circuit terminal A may cause this DTC to set. |
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
• | J 23738-A Mityvac |
• | J 35555 Metal Mityvac |
⇒ | If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle . |
Important:
• The harness connectors for the following sensors are the same configuration but are not interchangeable. • Review the engine controls schematics for the BARO sensor and for the SCIAP sensor and note the circuit colors. • Inspect the wiring harness of the BARO sensor for the proper connections. • Inspect the wiring harness of the SCIAP sensor for the proper connections.
• | Damaged components |
• | Loose or improper installation |
• | An air flow restriction |
• | A cracked or restricted SCIAP sensor vacuum hose |
• | An intake manifold leak |
⇒ | If greater than the specified range, test the low reference circuit terminal A or an open/high resistance. If the circuit tests normal, replace the ECM. |
⇒ | If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM. |
⇒ | If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM. |
⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM. |
⇒ | If less than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the ECM. |
Important: You must perform the Circuit/System Testing to verify the integrity of the sensor circuits before proceeding with the Component Testing.
THEN
Ignition ON, Engine OFF, MAP Sensor Parameter | MAP Sensor Parameter With 5 Inches of Vacuum Applied | MAP Sensor Parameter With 10 Inches of Vacuum Applied |
---|---|---|
100 kPa | 79-87 kPa | 62-70 kPa |
95 kPa | 74-82 kPa | 57-65 kPa |
90 kPa | 69-77 kPa | 52-60 kPa |
80 kPa | 59-67 kPa | 42-50 kPa |
70 kPa | 49-57 kPa | 32-40 kPa |
60 kPa | 39-47 kPa | 22-30 kPa |
⇒ | If the voltage is not within the specified range or is erratic, replace the affected sensor. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for ECM replacement, setup, and programming |