Section 11.7
Manifold Absolute Pressure Sensor (Map Sensor) for the Series 50G Engine
Listed in Table "Air Inlet Pressure Diagnostic Codes for the Series 50G Engine" are the air inlet pressure diagnostic codes:
Parameter Identification Character (PID): A PID is a single byte character used in J 1587 messages to identify the data byte(s) that follow. PIDs in the range 0-127 identify single byte data, 128-191 identify double byte data, and 192-253 identify data of varying length.
Failure Mode Identifier (FMI): The FMI describes the type of failure detected in the subsystem and identified by the PID. The FMI and the PID combine to form a given diagnostic code defined in J 1587 within PID 194.
DDR Description |
Voltage |
PID |
FMI |
Information |
AIR INLET PRESSURE |
HIGH |
106 |
0 |
Indicates that the Manifold Absolute Pressure Sensor (MAP) has detected that engine intake manifold pressure has exceeded the recommended operating range. |
AIR INLET PRESSURE |
HIGH |
106 |
3 |
Indicates that the Manifold Absolute Pressure Sensor (MAP) input to the ECM has exceeded 95% (normally >4.75 volts) of the sensor supply voltage. This diagnostic condition is typically detected when there is an open sensor return circuit or the sensor signal circuit is shorted to the sensor +5 volt supply. |
AIR INLET PRESSURE |
LOW |
106 |
4 |
Indicated that the Manifold Absolute Pressure Sensor (MAP) input to the ECM has dropped below 5% (normally, 0.25 volts) of the sensor supply voltage. This diagnostic condition is typically: - An open sensor signal circuit- An open sensor signal circuit opens sensor +5 volt supply circuit- The sensor signal is shorted to the sensor return circuit or ground- The sensors +5 volt supply is shorted to sensor return circuit or to ground |
Listed in Table "Throttle Control Specifications for the Series 50G Engine" are the throttle control specifications:
DDR Description |
Circuit |
SID |
FMI |
Information |
Unrecognized SID or OIL PRS LOW* |
OPEN |
51 |
3 |
Indicates that the Throttle Power function that has been assigned to the ECM Auxiliary Output #3 circuit (S3) is open or is shorted to battery (+). This diagnostic condition is detected when the Throttle Power driver is OFF and the DDEC III ECM measures a high voltage on the circuit output. |
Unrecognized SID or OIL PRS LOW* |
SHORT TO GROUND |
51 |
4 |
Indicates that the Throttle Power function that has been assigned to the ECM Auxiliary Output #3 circuit (S3) is shorted to ground. This diagnostic condition is detected when the DDEC III ECM is unsuccessful in turning ON the Throttle Power driver output. The Throttle Power output is a high side driver, which means that the DDEC III ECM supplies battery (+) to the throttle power circuit to turn ON the function. |
Unrecognized SID or OIL PRS LOW* |
OPEN |
52 |
3 |
Indicates that the Throttle Power function that has been assigned to the ECM Auxiliary Output #4 circuit (T3) is open or is shorted to battery (+). This diagnostic condition is detected when the Throttle Power driver is OFF and the DDEC III ECM measures a high voltage on the circuit output. |
Unrecognized SID or OIL PRS LOW* |
SHORT TO GROUND |
52 |
4 |
Indicates that the Throttle Power function that has been assigned to the ECM Auxiliary Output #4 circuit (T3) is shorted to ground. This diagnostic condition is detected when the DDEC III ECM is unsuccessful in turning ON the Throttle Power driver output. The Throttle Power output is a high side driver, which means that the DDEC III ECM supplies battery (+) to the throttle power circuit to turn ON the function. |
PWM DRIVER #2 |
SHORT TO BATTERY (+) |
58 |
3 |
Indicates that the PWM DRIVER #2 circuit (Y1) output is shorted to battery (+). This diagnostic condition is detected when the DDEC III ECM is unsuccessful in turning ON the circuit function. NOTE: The DDEC III ECM supplies a switched ground to the PWM DRIVER #2 circuit to turn ON the circuit function. |
PWM DRIVER #2 |
OPEN |
58 |
4 |
Indicates that the PWM DRIVER #2 circuit (Y1) output is open or is shorted to ground. This diagnostic condition is detected when the PWM DRIVER #2 function is OFF and the DDEC III ECM measures a low voltage on the circuit output. |
Note: * All version 1.00 or version 2.00 Prolink 9000 DDR software occurred prior to assignment of natural gas engine throttle control diagnostics. As a result, the DDR, depending upon the version software installed, will display either of the following descriptions when diagnosing natural gas throttle position codes: "Unrecognized SID" or "OIL PRS LOW." Both descriptions are incorrect.
Listed in Table "Throttle Control Diagnostic Codes for the Series 50G Engine" are the throttle control diagnostic codes:
DDR Description |
Voltage |
PID |
FMI |
Information |
THROTTLE PLATE POS |
HIGH |
51 |
3 |
Indicates that the Throttle Plate Position Sensor input to the ECM has exceeded 95% (normally >4.75 volts) of the sensor supply voltage. This diagnostic condition is typically detected when there is an open sensor return circuit or the sensor signal circuit is shorted to the sensor +5 volt supply. |
THROTTLE PLATE POS |
LOW |
51 |
4 |
Indicates that the Throttle Plate Position Sensor input to the ECM has dropped below 5% (normally < 0.25 volts) of the sensor supply voltage. This diagnostic is typically detected when there is: - An open sensor signal circuit- An open sensor +5 volt supply circuit- The sensor signal is shorted to the sensor return circuit or to ground |
THROTTLE PLATE POS |
HIGH |
51 |
0 |
Indicates that the Throttle Plate Position Sensor input to the ECM has indicated that the throttle plate has exceeded the recommended operating range. |
THROTTLE PLATE POS |
LOW |
51 |
1 |
Indicates that the Throttle Plate Position Sensor input to the ECM has indicated that the throttle plate has dropped below the recommended operating range. |
Listed in Table "Knock Sensors and Knock Interface Module Diagnostic Codes for the Series 50G Engine" are the knock sensor and knock interface module diagnostic codes:
DDR Description |
Voltage |
PID |
FMI |
Information |
Unrecognized SID |
HIGH |
67 |
3 |
Indicates that the knock sensor input to the ECM has exceeded 95% (normally >4.75 volts) of the sensor supply voltage. This diagnostic is typically detected when there is an open sensor return circuit or the sensor signal circuit is shorted to the sensor +5 volt supply. |
Unrecognized SID |
LOW |
67 |
4 |
Indicates that the knock sensor input to the ECM has dropped below 5% (normal < 0.25 volts) of the sensor supply voltage. This diagnostic is typically detected when there is: - An open sensor signal circuit- An open sensor +5 volt supply circuit- The sensor signal is shorted to the sensor return circuit or to ground- The sensor +5 volt supply is shorted to sensor return circuit or to ground |
Unrecognized SID |
HIGH |
67 |
0 |
Indicates that the knock interface module has detected that the engine knock level has exceeded the first level of the recommended engine operational level. |
Unrecognized SID |
MECHANICAL FAULT |
67 |
7 |
Indicates that the knock interface module has detected that the engine knock level has exceeded the second level of the recommended engine operational range. |
The GFI monitor screen for the Series 50G engine is graphically illustrated; see Figure "GFI Monitor Screen for Series 50G Engine" .

Figure 1. GFI Monitor Screen for Series 50G Engine
Series 50 Service Manual - 6SE50 |
Generated on 10-13-2008 |