Pgm-Fi Troubleshooting Information; General Troubleshooting; System Description - Honda NC700XA Service Manual

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PGM-FI TROUBLESHOOTING INFORMATION

GENERAL TROUBLESHOOTING

Intermittent Failure
The term "intermittent failure" means a system may have had a failure, but it checks OK now. If the MIL does not come on, check
for poor contact or loose pins at all connectors related to the circuit that of the troubleshooting. If the MIL was on, but then went out,
the original problem may be intermittent.
Opens and Shorts
"Opens" and "Shorts" are common electrical terms. An open is a break in a wire or at a connection. A short is an accidental
connection of a wire to ground or to another wire. In simple electronics, this usually means something will not work at all. With ECM/
PCMs this can something mean something work, but not the way it's supposed to.
If the MIL has come on
Refer to DTC READOUT (page 4-12).
If the MIL did not stay on
If the MIL did not stay on, but there is a driveability problem, do the SYMPTOM TROUBLESHOOTING (page 4-7).

SYSTEM DESCRIPTION

SELF-DIAGNOSIS SYSTEM
The PGM-FI system is equipped with the self-diagnostic system. When any abnormality occurs in the system, the ECM/PCM turns
on the MIL and stores a DTC in its erasable memory.
FAIL-SAFE FUNCTION
The PGM-FI system is provided with a fail-safe function to secure a minimum running capability even when there is trouble in the
system. When any abnormality is detected by the self-diagnosis function, running capability is maintained by pre-programed value
in the simulated program map. When any abnormality is detected in the injector, the fail-safe function stops the engine to protect it
from damage.
DTC
• The DTC is composed of a main code and a sub code and it is displayed as a hyphenated number when retrieved from the
ECM/PCM with the HDS pocket tester.
The digits in front of the hyphen are the main code, they indicate the component of function failure.
The digits behind the hyphen are the sub code, they detail the specific symptom of the component or function failure.
For example, in the case of the TP sensor:
– DTC 08 – 1 = (TP sensor voltage) – (lower than the specified value)
– DTC 08 – 2 = (TP sensor voltage) – (higher than the specified value)
• The MAP, ECT, TP and IAT sensor diagnosis will be made according to the voltage output of the affected sensor.
If a failure occurs, the ECM/PCM determines the Function Failure, compares the sensor voltage output to the standard value,
and then outputs the corresponding DTC to the HDS pocket tester.
For example:
– If the input voltage line (A) on the MAP sensor is opened, the ECM/PCM detects the output voltage is about 5 V, then the DTC
1-2 (MAP sensor circuit high voltage) will be displayed.
– If the input voltage line (B) on the TP sensor is opened, the ECM/PCM detects the output voltage is 0 V, then the DTC 8-1 (TP
sensor circuit low voltage) will be displayed.
MIL Blink Pattern
• If the HDS pocket tester is not available, DTC can be read from the
ECM/PCM memory by the MIL [1] blink pattern.
• The number of MIL blinks is the equivalent the main code of the DTC
(the sub code cannot be displayed by the MIL).
• The MIL will blink the current DTC, in case the ECM/PCM detects the
problem at present, when the ignition switch ON and engine stop switch
" " or idling with the sidestand down. The MIL will stay ON when the
engine speed is over 1,850 min
• The MIL has two types of blinks, a long blink and short blink. The long
blinking lasts for 1.3 seconds, the short blinking lasts for 0.3 seconds.
One long blink is the equivalent of ten short blinks. For example, when
two long blinks are followed by five short blinks, the MIL is 25 (two long
blinks = 20 blinks, plus five short blinks).
• When the ECM/PCM stores more than one DTC, the MIL will indicate
them by blinking in the order from the lowest number to highest number.
MIL Check
When the ignition switch is turned ON and engine stop switch " " the MIL will stay on for a few seconds, then go off. If the MIL does
not come on, troubleshoot the MIL circuit (page 4-63).
-1
(rpm) or with the sidestand up.
[1]
PGM-FI SYSTEM
4-11