PRE-RELEASE
DTC P0191
| DTC P0191 |
| Diagnostic Instructions |
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Perform the
Diagnostic System Check - Vehicle
prior to using this diagnostic procedure.
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Review
Strategy Based Diagnosis
for an overview of the diagnostic approach.
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Diagnostic Procedure Instructions
provides an overview of each diagnostic category.
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| DTC Descriptors |
DTC P0191
Fuel Rail Pressure Sensor Performance
| Diagnostic Fault Information |
| Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
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5 V Reference Voltage
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P0192, P0193, P0641
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P0192
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P0641
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P0191
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Fuel Rail Pressure Sensor Signal
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P0192
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P0192
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P0193
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P0191
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Low Reference
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-
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P0193, P0506
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-
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P0191
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| Circuit/System Description |
The fuel rail fuel pressure sensor detects fuel pressure within the fuel rail. The engine control module (ECM) provides a 5 V reference voltage on the 5 V reference circuit and ground on the low reference circuit. The ECM receives a varying signal voltage on the signal circuit. The ECM monitors the voltage in the fuel pressure sensor circuits of the fuel rail. When the fuel pressure is high, the signal voltage is high. When the fuel pressure is low, the signal voltage is low.
| Conditions for Running the DTC |
Condition 1
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DTC P0016, P0017, P0068, P0090, P0091, P0092, P0096, P0097, P0098, P00C8, P00C9, P00CA, P0101, P0102, P0103, P0106, P0107, P0108, P0111, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0128, P0178, P0179, P0192, P0193, P0201, P0202, P0203, P0204, P0222, P0223, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0300, P0301, P0302, P0303, P0304, P0335, P0336, P0340, P0341, P0351, P0352, P0353, P0354, P0365, P0366, P0506, P0507, P0627, P0628, P0629, P0697, P06A3, P0722, P1248, P1249, P124A, P124B, P1682, P16F3, P2101, P2122, P2123, P2127, P2128, P2135, P2138, P2147, P2148, P2150, P2151, P2153, P2154, P2156, P2157, P2269 is not set.
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The engine is running.
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The vehicle speed is less than or equal to 5 km/h (3.11 mph).
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DTC P0191 runs continuously when the above conditions have been met.
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Condition 2 and 3
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DTC P0016, P0017, P0068, P0090, P0091, P0092, P0096, P0097, P0098, P00C8, P00C9, P00CA, P0101, P0102, P0103, P0106, P0107, P0108, P0111, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0128, P0178, P0179, P0192, P0193, P0201, P0202, P0203, P0204, P0222, P0223, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0300, P0301, P0302, P0303, P0304, P0335, P0336, P0340, P0341, P0351, P0352, P0353, P0354, P0365, P0366, P0506, P0507, P0627, P0628, P0629, P0697, P06A3, P0722, P1248, P1249, P124A, P124B, P1682, P16F3, P2101, P2122, P2123, P2127, P2128, P2135, P2138, P2147, P2148, P2150, P2151, P2153, P2154, P2156, P2157, P2269 is not set.
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The engine is running.
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The engine speed is between 1,000-3,000 RPM.
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DTC P0191 runs continuously when the above conditions have been met.
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Condition 4
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DTC P0016, P0017, P0068, P0090, P0091, P0092, P0096, P0097, P0098, P00C8, P00C9, P00CA, P0101, P0102, P0103, P0106, P0107, P0108, P0111, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0128, P0178, P0179, P0192, P0193, P0201, P0202, P0203, P0204, P0222, P0223, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0300, P0301, P0302, P0303, P0304, P0335, P0336, P0340, P0341, P0351, P0352, P0353, P0354, P0365, P0366, P0506, P0507, P0627, P0628, P0629, P0697, P06A3, P0722, P1248, P1249, P124A, P124B, P1682, P16F3, P2101, P2122, P2123, P2127, P2128, P2135, P2138, P2147, P2148, P2150, P2151, P2153, P2154, P2156, P2157, P2269 is not set.
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The engine is running.
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The engine speed is less than or equal to 2,000 RPM.
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DTC P0191 runs continuously when the above conditions have been met.
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| Conditions for Setting the DTC |
Condition 1
The difference between the measured high pressure and the commanded high pressure is less than or equal to -650 kPa (-94 psi) or greater than or equal to 600 kPa (87 psi) for greater than 3 s.Condition 2
The difference between the relief pressure and the measured high pressure is less than or equal to -5000 kPa (-725 psi) for greater than 2 s.Condition 3
The difference between the commanded high pressure and the measured high pressure is greater than or equal to 3000 kPa (435 psi) and the modeled injection pressure is greater than or equal to 3000 kPa (435 psi) for greater than 3 s.Condition 4
The difference between the measured maximum high pressure and the measured minimum high pressure is less than or equal to 100 kPa (14.5 psi) for greater than 60 s.| Action Taken When the DTC Sets |
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DTC P0191 is a Type A DTC.
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A message center or an indicator may display Reduced Engine Power.
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| Conditions for Clearing the DTC |
DTC P0191 is a Type A DTC.
| Diagnostic Aids |
A condition with the fuel tank fuel pump module or the fuel pump control module may set this DTC.
| Reference Information |
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Fuel System Description
Electrical Information Reference
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Circuit Testing
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Connector Repairs
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Testing for Intermittent Conditions and Poor Connections
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Wiring Repairs
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DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
| Circuit/System Verification |
| 1. |
Observe the scan tool DTC information. Verify that DTC P0627, P0628, P0629, P0641, P069E or U0109 is not set.
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| 2. |
If any of the DTCs are set, refer to
Diagnostic Trouble Code (DTC) List - Vehicle
.
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| 3. |
Engine idling, observe the scan tool Fuel Rail Pressure Sensor parameter. The pressure should be approximately 1.9-2.1 Mpa (279-305 psi).
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| 4. |
Engine idling, the scan tool Fuel Rail Pressure Sensor should be close to the scan tool Desired Fuel Rail Pressure. As the engine speed increases, the Desired Fuel Rail Pressure and the Fuel Rail Pressure Sensor should closely match each other.
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| 5. |
Move related harnesses/connectors of the B47 fuel rail fuel pressure sensor and verify the engine does not stumble, stall, or change engine speed.
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If the engine stumbles, stalls, or changes engine speed, test or repair the suspected harness or connection.
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| 7. |
Observe the DTC information with a scan tool, DTC P0191 should not set.
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| 8. |
Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
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| Circuit/System Testing |
| 1. |
Ignition OFF, disconnect the fuel injector multi-way harness connector X160.
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| 2. |
Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Test for less than 5 Ω between the low reference circuit terminal 5 and ground. |
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| 3. |
If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.
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Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal 11 and ground.
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| 5. |
If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
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If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
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Ignition ON, verify the scan tool Fuel Rail Pressure Sensor voltage parameter is less than 0.02 V.
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If greater than the specified value, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
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Connect a 3 A fused jumper wire between the signal circuit terminal 12 and the 5 V reference circuit terminal 11. Verify the scan tool Fuel Rail Pressure Sensor Voltage parameter is greater than 4.96 V.
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If less than the specified value, test the signal circuit for an open/high resistance or a short to ground. If the circuit tests normal, replace the K20 ECM.
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| 11. |
Ignition OFF, remove the intake manifold.
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| 12. |
Connect the fuel injector multi-way harness connector X160.
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Disconnect the B47 fuel rail fuel pressure sensor connector. |
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Ignition OFF, test for less than 5 Ω between the low reference circuit terminal C and ground.
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If greater than the specified range, test the low reference circuit for an open/high resistance.
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Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal A and ground.
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If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance.
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If greater than the specified range, test the 5 V reference circuit for a short to voltage.
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Ignition ON, verify the scan tool Fuel Rail Pressure Sensor voltage parameter is less than 0.02 V.
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| 20. |
If greater than the specified value, test the signal circuit for a short to voltage.
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| 21. |
Connect a 3 A fused jumper wire between the signal circuit terminal B and the 5 V reference circuit terminal A. Verify the scan tool Fuel Rail Pressure Sensor voltage parameter is greater than 4.96 V.
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| 22. |
If less than the specified value, test the signal circuit for an open/high resistance or a short to ground.
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| 23. |
If all circuits test normal, replace the B47 fuel rail fuel pressure sensor.
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| Repair Instructions |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
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Fuel Injection Fuel Rail Fuel Pressure Sensor Replacement
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Control Module References
for ECM replacement, setup, and programming
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