Fuel & Emissions


Troubleshooting Procedures
I. How To Begin Troubleshooting
When the Malfunction Indicator Lamp (MIL) has been reported on, or there is a driveability problem, use the appropri-
ate procedure below to diagnose and repair the problem.
A. When the MIL has come on:
1. Connect the Honda PGM Tester or an OBD-II
scan tool to the 16P Data Link Connector (DLC)
located under the glove box behind a removable
2. Turn the ignition switch ON.
3. Honda PGM Tester: Begin troubleshooting as
indicated by the tester. The DTC troubleshooting
flowcharts are not needed with the tester; follow
the tester’s prompts.
OBD-II scan tool: Check the DTC and note it. Also
check and note the freeze frame data. Refer to
the Diagnostic Trouble Code Chart and begin
• See the OBD-II scan tool or Honda PGM Tester user’s manuals for specific operating instructions.
• The scan tool or tester can read the Diagnostic Trouble Codes (DTC), freeze frame data, current data, and other
Engine Control Module (ECM) data.
• Freeze frame data indicates the engine conditions when the first malfunction, misfire or fuel trim malfunction
was detected. It can be useful information when troubleshooting.
B. When the MIL has not come on, but there is a driveability problem, refer to the Symptom Chart on page 11-42.
C. DTCs will be indicated by the blinking of the Malfunction Indicator Lamp (MIL) with the SCS service connector con-
• Connect the SCS service connector to Service Check Connector as shown. (The 2P Service Check Connector is
located under the dash on the passenger’s side of the car.) Turn the ignition switch on.
07PAZ – 0010100

II. Engine Control Module (ECM) Reset Procedure
Either of the following actions, will reset the ECM.
• Using the OBD-II scan tool or Honda PGM Tester to clear the ECM’s memory.
NOTE: See the OBD-II scan tool or Honda PGM Tester user’s manuals for specific operating instructions.
• Turn the ignition switch OFF. Remove the CLOCK (7.5 A) fuse from the under-hood fuse/relay box for 10 seconds.
(7.5 A) FUSE
III. Final Procedure (this procedure must be done after any troubleshooting)
1. Remove the SCS Service Connector if it is connected.
NOTE: If the SCS service connector is connected and there are no DTCs stored in the ECM, the MIL will stay on
when the ignition switch is turned on.
2. Do the ECM Reset Procedure.
3. Turn the ignition switch OFF.
4. Disconnect the OBD-II scan tool or Honda PGM Tester from the Data Link Connector,

Troubleshooting Procedures
If the inspection for a particular code requires voltage or resistance checks at the ECM connectors, remove the bulkhead
panels. Unbolt the ECM. check the system according to the procedure described for the appropriate code(s) listed on the
following pages.
How to Use the Backprobe Sets
Connect the backprobe adapters to the stacking patch cords, and connect the cords to a multimeter. Using the wire insula-
tion as a guide for the contoured tip of the backprobe adapter, gently slide the tip into the connector from the wire side
until it comes in contact with terminal end of the wire.
(Commercially available) or
KS – AHM – 32 – 003
07SAZ – 001000A (two required) BACKPROBE ADAPTER

• Puncturing the insulation on a wire can cause poor or intermittent electrical connections.
• Bring the tester probe into contact with the terminal from the connector side of wire harness connectors in the engine
compartment. For female connectors, just touch lightly with the tester probe and do not insert the probe.

Troubleshooting Procedures
Symptom Chart
Listed below are symptoms and probable causes for problems that DO NOT cause the Malfunction Indicator Lamp (MIL) to
come on.
If the MIL was reported on, go to page 11-38.
Troubleshoot each probable cause in the order listed (from left to right) until the symptom is eliminated.
The probable cause and troubleshooting page reference can be found on next page.
Troubleshoot for misfire on pages 11-90, 11-94
Other Probable Causes:
Engine will not start
— Compression
— Engine locked up
— Timing belt
— Starting system
— Overheating
— Battery

11-61, 11-62
11-132, 11-139
Section 23
See DTC chart
See DTC chart
See DTC chart
See DTC chart
See DTC chart
11-121, 11-124
Probable Cause List
Main Menu
Table of Contents
Probable Cause List
Probable Cause Page System
1 11-61,11-62 Engine Control Module (ECM)
2 11-132, 11-139 Fuel pressure and fuel pump relay
3 11.143 PGMŸFÏnäàïn {Je} W`
4 Section 23 Ignition system i
5 ⊲ See DTC chart Crankshaft Fosition/Cylihvaevr’fios‘itiign sensor circuit V 7 r
6 See DTC chart Intake Air Temperature (IAT) sensor circuit
7 11-128 Idle speed adjustment
8 11-151 Throttle body
9 11-150 Throttle cable
10 See DTC chan Manifold Absolute Pressure (MAP) sensor
11 See DTC chart Throttle Position (TP) sensor J
12 See DTC chan Barometric pressure (BARO) sensor
13 11-121, 11-124 A/T gear position signal or clutch switch signal
14 11-126 Brake switch signal
15 7 11-149 Air Cleaner
16 11-154 Intake Air Bypass (IAB) control system and intake air pipe
17 11-159 Three Way Catalytic Converter (TWC)
18 11-167 Evaporative emission (EVAP) control
19 W v Л А contaminated fuel v “w;
Troubleshooting Procedures (cont’d)
ECM Data
By connecting the OBD-II scan tool or the Honda PGM Tester to the 16P data link connector (DLC), various data can be
retrieved from the ECM. The items listed in the table below conform to the SAE recommended practice.
The Honda PGM Tester also reads data beyond that recommended by SAE.
Understanding this data will help to find the causes of intermittent failures or engine problems.
• The “operating values” given below are approximate values and may be different depending on the environment and
the individual car.
• Unless noted otherwise, “at idle speed” means idling with the engine completely warmed up, A/T in or position,
M/T in neutral, and the A/C and all accessories turned off.

Main Menu
Table of Contents
Data Description Operating Value Freeze Data
H028 Loop status is indicated as “open” or “closed”. At idle speed: closed
Feedback Closed: Based on the H025 output, the ECM deter-
Loop Status mines the air/fuel ratio and controls the amount of
(Bank l: Rear) injected fuel. O
(Bank 2: Front) Open: Ignoring H028 output, the ECM refers to signals
from the TP, MAP, and ECT sensors to control the
amount of injected fuel.
Short Term The air/fuel ratio correction coefficient for correcting -30% – +43%
Fuel Trim the amount of injected fuel when HOZS feedback is in
(Bank 1: Rear) the closed loop status. When the signal from the H025
(Bank 2: Front) is weak, short term fuel trim gets higher, and the ECM
increases the amount of injected fuel. The air/fuel ratio
. . . O
gradually gets richer, causmg a higher H025 output.
Consequently, the short term fuel trim is lowered, and
the ECM reduces the amount of injected fuel. This
cycle keeps the air/fuel ratio close to the stoichiometric
ratio when in closed loop status.
Long Term Long term fuel trim in computed from short term fuel — 19% – +25%
Fuel Trim trim and indicates changes occuring in the fuel supply
(Bank 1: Rear) system over a long period. O
(Bank 2: Front) If long term fuel trim is higher than 1.00, the amount of
injected fuel must be increased. If it is lower than 1.00,
the amount of injected fuel must be reduced.
Intake Air The IAT sensor converts intake air temperature into With cold engine:
Temperature voltage and signals the ECM. When intake air tempera- Same as ambient tempere O
(IAT) ture is low, the internal resistance of the sensor ature and ECT
increases, and the voltage signal is higher.
Throttle Based on the accelerator pedal position, the opening At idle: Approx. 10%
Position angle of the throttle valve is indicated. At full throttle: Approx. O
Ignition The ignition advance angle is set by the ECM. The ECM AI idle SPEEd! 15 i 2°
Timing matches ignition timing to the driving conditions. BTDC With the SCS Service x
connector connected.
Calculated CLV is the engine load calculated from the MAP data. At idle speed:
Load Value 15-35% O
(CLV) At 2,500 rpm with no load:
12 — 30%