P1093

p0540

Then I'll tell ya if it makes sense.......... :confused:

Thanks,

T:(NY

DTC P1093
Circuit Description
The engine control module (ECM) uses the fuel rail pressure (FRP) sensor to determine fuel pressure to the fuel injectors. This is then compared to the calculated target fuel pressure as determined by the ECM. The ECM adjusts the FRP by modulating the duty cycle of the control driver of the fuel pressure regulator. Injector pulse duration is determined by the measured rail pressure and the target injection fuel into each cylinder. If a sensor circuit malfunction is detected, or the commanded fuel injection pump flow is not within the proper range for a given engine load and speed, DTC will be set.

Conditions for Running the DTC
DTCs P0192, P0193, or P1635 are not set.
The ignition is ON.
Conditions for Setting the DTC
The difference between commanded fuel pressure and actual fuel pressure is more than 20 MPa.

or

The FRP Regulator Fuel Flow is more than 15,000 mm³ at 800 RPM, or more than 38,000 mm³ at 2,000 RPM.

Action Taken When the DTC Sets (California)
The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.
Action Taken When the DTC Sets (Federal)
The control module stores the DTC information into memory when the diagnostic runs and fails.
The malfunction indicator lamp (MIL) will not illuminate.
The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.
The driver information center, if equipped, may display a message.
Conditions for Clearing the MIL/DTC (California)
The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
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.
Conditions for Clearing the DTC (Federal)
A current DTC Last Test Failed clears when the diagnostic runs and passes.
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 DTC.
Diagnostic Aids
This DTC does not set for an idle condition.

A number of conditions may cause DTC P0087 and DTC P1093 to set:

Excessive fuel return to the tank
A fuel injection pump failure
A fuel pressure regulator (RPCV) failure
If you have to prime the fuel system, check for the following conditions:

A restricted fuel supply line
A fuel supply line air leak. Refer to Fuel System Diagnosis .
A sticking Fuel Pressure Regulator may set this DTC. Refer to Fuel System Diagnosis - High Pressure Side . Perform this test under the conditions for which the DTC set.

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DTC P0540
Circuit Description
The engine control module (ECM) uses an intake air heater (IAH) to warm the incoming air for proper cylinder combustion. The ECM grounds the control coil of the IAH relay to energize the heater during cold operation. If the ECM detects voltage on the IAH circuit when the relay is commanded OFF, or incorrect voltage when the relay is commanded ON, a DTC will set.

Conditions for Running the DTC
The battery voltage is between 10-18 volts.
The intake air temperature (IAT) is less than 23°C (73°F) with the engine running. OR
The coolant temperature is less than 49°C (121°F) with the ignition ON, engine OFF for more than 3 seconds.
Conditions for Setting the DTC
The heater line voltage is more than 8.1 volts with the relay OFF.

OR

The heater line voltage is between 3.8-8.1 volts with the ignition OFF.

AND

The heater line voltage is less than 0.5 volt below battery voltage with the ignition ON.

OR

The heater line voltage is less than 3.8 volts with the relay OFF.

AND

The reference line voltage is low with the relay OFF.

Action Taken When the DTC Sets
The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
Conditions for Clearing the MIL/DTC
The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
Clear the MIL and the DTC with a scan tool.

[QUOTE=Max Payne]DTC P1093
Circuit Description
The engine control module (ECM) uses the fuel rail pressure (FRP) sensor to determine fuel pressure to the fuel injectors. This is then compared to the calculated target fuel pressure as determined by the ECM. The ECM adjusts the FRP by modulating the duty cycle of the control driver of the fuel pressure regulator. Injector pulse duration is determined by the measured rail pressure and the target injection fuel into each cylinder. If a sensor circuit malfunction is detected, or the commanded fuel injection pump flow is not within the proper range for a given engine load and speed, DTC will be set.


Max, do you know if this is a "learned thing" that the control module figures and adjusts over time to meet some ideal target value or does it do right out of the box

I do not believe it to be learned, rather a set parameter based on an algorithm of many inputs.