Honda Civic. Manual — part 766

12. Disconnect ECM/PCM connector A (44P).
13. Connect the ECM/PCM connector A (44P) terminal No. 5 to body ground with

a jumper wire.

Fig. 58: Connecting ECM/PCM Connector A (44P) Terminal No. 5 To
Body Ground With Jumper Wire

14. Turn the ignition switch ON (II).

Does the A/C condenser fan run on high?

YES - Check for loose wires or poor connections at ECM/PCM connector A
(44P) terminal No. 5. If the connections are good, substitute a known-good
ECM/PCM, and recheck. If the symptom/indication goes away, replace the
original ECM/PCM, R18A1 engine (see ECM/PCM REPLACEMENT ),
K20Z3 engine (see ECM REPLACEMENT ).

NO - Repair open in the wire between the A/C condenser fan relay and the
ECM/PCM.

15. Turn the ignition switch to LOCK (0).
16. Remove A/C diode B from the under-hood fuse/relay box.
17. Turn the ignition switch ON (II).

NOTE:

This step must be done to protect the engine control
module (ECM)/powertrain control module (PCM) from
damage.

2008 Honda Civic EX

2006-08 HVAC Heating/Air Conditioning - Civic (All Except Hybrid)

18. Measure the voltage between the A/C diode B 2P socket terminal No. 2 and

body ground.

Fig. 59: Measuring Voltage Between A/C Diode B 2P Socket Terminal No.
2 And Body Ground

Is there battery voltage?

YES - Go to step 19.

NO - Replace the under-hood fuse/relay box (see REMOVAL AND
INSTALLATION ).

19. Using the diode setting on a DVOM, check for current flow in both directions

between the A/C diode B terminals No. 1 and No. 2.

Fig. 60: Checking Current Flow In Both Directions Between A/C Diode B
Terminals No. 1 And No. 2

Is there current flow in only one direction?

YES - Replace the under-hood fuse/relay box (see REMOVAL AND

2008 Honda Civic EX

2006-08 HVAC Heating/Air Conditioning - Civic (All Except Hybrid)

INSTALLATION ).

NO - Replace A/C diode B.

A/C COMPRESSOR CLUTCH CIRCUIT TROUBLESHOOTING

1. Check the No. 20 (7.5 A) fuse in the under-hood fuse/relay box, and the No. 36

(10 A) fuse in the under-dash fuse/relay box.

Are the fuses OK?

YES - Go to step 2.

NO - Replace the fuses and recheck. If the fuses blow again, check for a short
in the No. 20 (7.5 A) and No. 36 (10 A) fuses circuit.

2. Connect the HDS to the DLC.
3. Start the engine.
4. Turn on the A/C on the HVAC control unit.
5. Check the A/C CLUTCH in the PGM-FI Data List with the HDS at idle.

HDS A/C VALUES

NOTE:

It is normal for the A/C compressor to turn off under
certain conditions, such as low idle, high engine
coolant temperature, or hard acceleration.

Do not use this troubleshooting procedure if the fans
are also inoperative with the A/C on. Refer to the
SYMPTOM TROUBLESHOOTING INDEX.

Before doing any symptom troubleshooting, check for
powertrain DTCs, R18A1 engine (see GENERAL
TROUBLESHOOTING INFORMATION ), K20Z3 engine
(see GENERAL TROUBLESHOOTING INFORMATION ).

ECT sensor 2

176-212 °F (80-100 °C)

TP sensor

About 0.5 V at idle

2008 Honda Civic EX

2006-08 HVAC Heating/Air Conditioning - Civic (All Except Hybrid)

Are all the values within specifications?

YES - Go to step 6.

NO - Troubleshoot the value that is not within the specfications.

6. Turn the ignition switch to LOCK (0).
7. Remove the A/C compressor clutch relay from the under-hood fuse/relay box,

and test it (see POWER RELAY TEST ).

Is the relay OK?

YES - Go to step 8.

NO - Replace the A/C compressor clutch relay.

8. Measure the voltage between the A/C compressor clutch relay 4P socket

terminal No. 1 and body ground.

Fig. 61: Measuring Voltage Between A/C Compressor Clutch Relay 4P
Socket Terminal No. 1 And Body Ground

Is there battery voltage?

YES - Go to step 9.

RPM

More than 670

A/C Switch

ON

A/C Clutch

ON

2008 Honda Civic EX

2006-08 HVAC Heating/Air Conditioning - Civic (All Except Hybrid)