Error code 33 (some advise required, please)

[Dave XJ]

Hi all

Just discovered today that when the Xj is idling it will at random almost stall, then it recovers and idles as per normal.

I did a diagnostic and discovered I have an error code 33 (air conditioning relay clutch relay).

Anyone had this problem? and if so what was the fix.

Thanks in advance.

[kik]

You could try just re-setting the computer.
To do this you need to remove one battery terminal then climb in the car and hold the ignition key in the start position for 30 secs.

Re-connect the terminal and let the car idle and reset itself.

Failing that I would assume that the relay is crook,or that the switch in the dash has intermitent shorting causing the compressor clutch to activate at random.


Just my thoughts kik.

[Dave XJ]

Thanks, I will give it a shot, much appreciated.

[bobmac]

Kik & Go jeep, Re cancelling computer codes. My 95 XJ check engine light came on a week or so back. Every thing ran OK, nothing untoward has happened since. I shut the engine off & restarted & since then the light has not come on. I accessed the codes as suggested & it throws up code 14 twice. I have tried both disconnecting the
battery overnight &, as suggested by kik disconnecting the battery ( I disconnected
the earth lead ) & turning the key to the start position etc. Neither method worked.
Another question, I only have a Haynes manual, & it says to use a high impedance
digital voltmeter to test the MAP sensor. I do not think my voltmeter is a high
impedance (Idont know what it is). bridging a-b terminals ,engine off Ign. on I get 0 volts, idling 0 volts. a-c terminals, engine off, Ign. on 5 volts .Is it safe to assume theMAP sensor is U/S ? What affect does a faulty MAP sensor have on a
Cherokee? Thanks for any info. bobmac.

[kik]

Code 14 is certainly your MAP sensor that is crook.

MAP refers to "Manifold Absolute Pressure" sensor, a variable resistor used to monitor the difference in pressure between the intake manifold at outside atmosphere.
This information is used by the engine computer to monitor engine load (vacuum drops when the engine is under load or at wide open throttle). When the engine is under load, the computer may alter spark timing and the fuel mixture to improve performance and emissions.

This also intereferes with the o2 sensor,causing false readings and therefore wrong fuel mixtures and wrong timing advance/retardation.

Using a multimeter is really of no use if the fault is intermittent,because the resistor is variable,you need to know what value it is static as well as its total value,this cannot be achieved unless on a dyno.

Call Mascot and order a new unit,they are quite easy to fit.

Extracting Fault Codes:
Turn the ignition switch ON, OFF, ON, OFF, ON and observe the CHECK ENGINE LIGHT. The CHECK ENGINE LIGHT should begin to flash a series of codes. The flashes will be separated by short an long pauses. The long pauses separate the "ones" and "tens" positions, and each code from the next. A code 55 will be displayed at the end of the test.

Hope this helps kik.

[kik]

Originally Posted by bobmac

Another question, I only have a Haynes manual, & it says to use a high impedance
digital voltmeter to test the MAP sensor. I do not think my voltmeter is a high
impedance (Idont know what it is). bridging a-b terminals ,engine off Ign. on I get 0 volts, idling 0 volts. a-c terminals, engine off, Ign. on 5 volts .Is it safe to assume theMAP sensor is U/S ? What affect does a faulty MAP sensor have on a
Cherokee? Thanks for any info. bobmac.

Just to clear this little matter for you Bob,impedance is measured using the OHM's scale on your meter,imepedance is the measurement in which resistance is measured,the term "voltmeter" obviously had you a tad confused there.

Using OHM's law you need but one element to determine the total resitance of a circuit,you already gathered one one 5 Volts, 5 Volts from a 35 amp source equates to 0.14286 Ohm's (static).

[bobmac]

Hi Kik,This is bobmac, thanks for the reply to my computer problem, looks like i will have to pick up a MAP sensor tomorrow somewhere. It is now 9.55pm in Perth. I have just returned from a 645 Km trip, left Perth at 8.30am this morning, & arrived back at 8.00 pm. I cruised at 2000RPM & averaged 12.1litres/100Km.with 4 up.I think I used to do a bit better than this. Problem is I will be off at 8am Thurs.on 2500Km. trip, but this one will take 10 days.( Have friends over from Brisbane) I am a qualified (retired) mechanic, but got out of the nuts & bolts side about 30 yearsago& became a designer of heavy all wheel drive specialised trucks, so I was out before computers came in.So, I depend upon the younger generation when computers of any sort are mentioned.Back to the computer codes.I have no trouble accessing the codes, but I cant seem to erase the memory. My idea (which may be wrong)was to erase the code & then see if it came up again, is this right or wrong?anyhow, thanks for your help(.I still remember how to fix HR Holdens, ( I think) bobmac .