Honda Civic. Manual — part 781

1. Connect the Honda Diagnostic System (HDS) to the data link connector (DLC)

(see step 2 on HOW TO USE THE HDS (HONDA DIAGNOSTIC
SYSTEM) ).

2. Turn the ignition switch ON (II).
3. Make sure the HDS communicates with the vehicle and the ECM. If it doesn't,

troubleshoot the DLC circuit (see DLC CIRCUIT TROUBLESHOOTING ).

4. Check for DTCs. If a DTC is present, diagnose and repair the cause before

continuing with this test.

5. Start the engine. Hold the engine speed at 3,000 rpm without load (in neutral)

until the radiator fan comes on, then let it idle.

6. Check the idle speed (see IDLE SPEED INSPECTION ).
7. Jump the SCS line with the HDS.
8. Connect the timing light to the service loop (white tape).

Fig. 3: Identifying Ignition Timing Mark
Courtesy of AMERICAN HONDA MOTOR CO., INC.

9. Aim the light toward the pointer (A) on the cam chain case. Check the ignition

timing under a no load condition (headlights, blower fan, rear window
defogger, and air conditioner are turned off).

Ignition Timing:

8 ° ±2 ° BTDC (RED mark (B)) at idle in Neutral

2008 Honda Civic EX

2006-08 ENGINE Ignition System (K20Z3) - Civic (Except Si)

Fig. 4: Checking Ignition Timing
Courtesy of AMERICAN HONDA MOTOR CO., INC.

10. If the ignition timing differs from the specification, check the cam timing. If

the cam timing is OK, update the engine control module (ECM) if it does not
have the latest software (see UPDATING THE ECM ), or substitute a known-
good ECM (see SUBSTITUTING THE ECM ), then recheck. If the system
work properly, and the ECM was substituted, replace the original ECM (see
ECM REPLACEMENT ).

11. Disconnect the HDS and the timing light.

IGNITION COIL REMOVAL/INSTALLATION

1. Remove the under-cowl panel (see FRONT GRILLE COVER

REPLACEMENT ).

2. Remove the ignition coil cover (A), disconnect the ignition coil connectors (B),

then remove the ignition coils (C).

2008 Honda Civic EX

2006-08 ENGINE Ignition System (K20Z3) - Civic (Except Si)

Fig. 5: Identifying Ignition Coil (With Torque Specifications)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

3. Install the ignition coils in the reverse order of removal.

IGNITION COIL RELAY CIRCUIT TROUBLESHOOTING

1. Check the No. 18 (15 A) fuse in the under-hood fuse/relay box.

Is the fuse OK?

YES -Go to step 2.

NO -Replace the fuse.

2. Remove the ignition coil relay from the under-hood fuse/relay box, and test it

(see POWER RELAY TEST ).

Is the relay OK?

YES -Go to step 3.

2008 Honda Civic EX

2006-08 ENGINE Ignition System (K20Z3) - Civic (Except Si)

NO -Replace the ignition coil relay.

3. Measure the voltage between ignition coil relay 4P socket terminal No. 2 and

body ground, then terminal No. 4 and body ground.

Fig. 6: Checking Voltage Between Ignition Coil Relay 4P Socket Terminal
No. 2 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?

YES -Go to step 4.

NO -Replace the under-hood fuse/relay box.

4. Check for continuity between ignition coil relay 4P socket terminal No. 2 and

the No. 1 ignition coil 3P connector terminal No. 3.

Fig. 7: Checking Continuity Between Ignition Coil Relay 4P Socket
Terminal No. 2 And No. 1 Ignition Coil 3P Connector Terminal No. 3

2008 Honda Civic EX

2006-08 ENGINE Ignition System (K20Z3) - Civic (Except Si)