Honda Civic. Manual — part 784

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/PCM. If it

doesn't, troubleshoot the DLC circuit (see DLC CIRCUIT
TROUBLESHOOTING ).

4. Check for DTCs (see GENERAL TROUBLESHOOTING

INFORMATION ). 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 the P or

N position (A/T) or neutral (M/T)) 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 No. 1 ignition coil harness.
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

M/T: 8 °±2 ° BTDC (RED mark (B) at idle in Neutral

A/T: 8 °±2 ° BTDC (RED mark (B) at idle in Park or Neutral

2008 Honda Civic EX

2006-08 ENGINE Ignition System (R18A1) - Civic (All Except Hybrid)

Fig. 3: Aiming Timing Light Toward Pointer
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Fig. 4: Identifying Timing Marks
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)/powertrain
control module (PCM) if it does not have the latest software (see UPDATING
ECM/PCM ), or substitute a known-good ECM/PCM (see SUBSTITUTING
THE ECM/PCM ), then recheck. If the system works properly, and the
ECM/PCM was substituted, replace the original ECM/PCM (see ECM/PCM
REPLACEMENT ).

11. Disconnect the HDS and the timing light.

2008 Honda Civic EX

2006-08 ENGINE Ignition System (R18A1) - Civic (All Except Hybrid)

IGNITION COIL REMOVAL/INSTALLATION

1. Disconnect the ignition coil connectors (A), then remove the ignition coils (B).

Fig. 5: Disconnecting Ignition Coil Connectors
Courtesy of AMERICAN HONDA MOTOR CO., INC.

2. 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.

NO -Replace the ignition coil relay.

2008 Honda Civic EX

2006-08 ENGINE Ignition System (R18A1) - Civic (All Except Hybrid)

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: Measuring 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. 1 and

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

Fig. 7: Checking For Continuity Between Ignition Coil Relay 4P Socket
Terminal No. 1
Courtesy of AMERICAN HONDA MOTOR CO., INC.

2008 Honda Civic EX

2006-08 ENGINE Ignition System (R18A1) - Civic (All Except Hybrid)