Honda NSA700A DN-1 2009, Service Manual

Page: 136 / 654

FUEL SYSTEM (PGM-FI)
PGM-FI TROUBLESHOOTING INFORMATION
GENERAL TROUBLESHOOTING
Intermittent Failure
The term "interm ittent fa ilu re " means a system m ay have had a failure, b ut it checks OK now . If the IVIL does not com e on,
check for poor contact or loose pins at all connectors related to the c irc u it th a t o f the tro u b le sh o o tin g . If the M IL w as on,
but then went out, the o rig in a l problem m ay be in te rm itte n t.
Opens and Shorts
"Opens" and "Shorts" are com m on electrical term s. An open is a break in a w ire o r at a connection. A sh o rt is an accidental
connection of a w ire to gro u n d or to anothe r w ire . In sim p le electronics, th is usu a lly m eans som ething w ill n ot w o rk at all.
With ECMs this can mean som ething w orks, b ut n ot the w ay it's supposed to.
If the MIL has come on
Refer to DTC READOUT (page 6-12).
If the MIL did n ot stay on
If the MIL did not stay on, but there is a d riv e a b ility pro b le m , do the SYMPTOM TROUBLESHOOTING (page 6-5).
SYSTEM DESCRIPTION
SELF-DIAGNOSIS SYSTEM
The PGM-FI system is equipped w ith the self-d ia g n o stic system . When any a b n o rm a lity occurs in the system , the ECM
turns on the MIL and stores a DTC in its erasable m em ory.
FAIL-SAFE FUNCTION
The PGM-FI system is pro vid e d w ith a fail-safe fu n c tio n to secure a m in im u m ru n n in g ca p a b ility even w h e n there is tro u b le
in the system. When any a b n o rm a lity is detected by the self-diagnosis fu n c tio n , run n in g c a p a b ility is m aintained by pre­
programed value in the sim ulated p rogram map. W hen any a b n o rm a lity is detected in th e injector(s), crankshaft p o sitio n
(CKP) sensor and/or cam shaft position (CMP) sensor, the fail-safe function stops the engine to protect it fro m damage.
DTC (Diagnostic T rouble Code)
• The DTC is com posed o f a m ain code and a sub code and it is displayed as a hyphenated num ber w hen retrieved fro m
the ECM w ith the HDS pocket tester.
The digits in fro n t o f the hyphen are the m ain code, th e y indicate the co m p o n e n t o f fu n c tio n failure.
The digits behind the hyphen are the sub code, they detail th e specific s y m p to m o f the com ponen t o r fu n c tio n failure.
For example, in the case o f the TP sensor:
- DTC 08 - 1 = (TP sensor voltage) - (lo w e r than the specified value)
- DTC 08 - 2 = (TP sensor voltage) - (h ig h e r th a n the specified value).
• The MAP, ECT, TP and IAT sensor diagno sis w ill be m ade according to the v o lta g e o u tp u t o f the affected sensor.
If a failure occurs, the ECM determ ines the Function Failure, com pares th e sensor vo lta g e o u tp u t to the standard value,
and then outputs the corresponding DTC to the HDS Pocket Tester.
For example:
- If the output line (A) on th e MAP sensor is opened, the ECM detects the o u tp u t voltage is about 5 V, then the DTC 1-2
(MAP sensor c irc u it high voltage) w ill be displayed.
- If the input voltage line (B) on the TP sensor is opened, the ECM detects the o u tp u t vo lta g e is 0 V, th e n the DTC 8-1 (TP
sensor circuit lo w voltage) w ill be displayed.
OUTPUT VOLTAGE
5V
5V
6-11