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Tim's Auto Repair, mechanic
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Experience:  Have owned a repair shop for 25 yrs.
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1994 s10: the esc module located..chevy..litre

Resolved Question:

where is the esc module located on a chevy 1994 s10 4 3 litre   and what is its duty or code 43
Submitted: 7 years ago.
Category: Chevy
Expert:  Tim's Auto Repair replied 7 years ago.


....when you have a problem with the esc it can be anything in the ignition system,timeing off,,the plugs,wires,rotor,dist,cap,knock sensor or the ignition control module...i will send you a chart to help you find this problem


please ACCEPT my answer so I can get credit for my work.i don't receive commission unless you do ..i'm not always going to be giving you good news,so please dont let this stand in the way of you accepting my does not cost you more money.we will still be able to communicate.. Bonuses and positive feedback are appreciated!if you are not satisfied with my answer,please do not leave bad feed back,i will gladly opt out and let another expert handle the question.PLEASE ASK IF YOU NEED MORE HELP

Ignition System
icon_note_blank.gif Notes Engine Component Locations" width="544" height="631"/> Engine Component Locations

Powertrain Controls - ECM/PCM


Code 43 - Electronic Spark Control (ESC) Circuit
Wiring Diagram For Code 43 - Electronic Spark Control (ESC) Circuit



Circuit Description :

Electronic spark control is accomplished with a module that sends a voltage signal to the ECM. As the knock sensor detects engine knock, the voltage from the ESC module to the ECM drops, and this signals the ECM to retard timing. The ECM will retard the timing when knock is detected and rpm is above about 900 rpm.

Code 43 means the ECM has been low voltage at CKT 485 terminal "B7" for longer than 5 seconds with the engine running or the system has failed the functional check.

This system performs a functional check once per start-up to check the ESC system. To perform this test, the ECMwill advance the spark when coolant is above 95~C and at a high load condition (near W.O.T.). The ECM then checks the signal at "B7" to see if a knock is detected. The functional check is performed once per start-up and if knock is detected when coolant is below 95~C (194~F), the test has passed and the functional check will not be run. If the functional check fails, the "Service Engine Soon" light will remain "ON" until ignition is turned "OFF" or until a knock signal is detected.

Test Description : Numbers below refer to circled numbers on the diagnostic chart.
  1. If the conditions for a Code 43 are present, the "Scan" will always display "YES." There should not be a knock at idle unless an internal engine problem, or a system problem exists.
  2. This test will determine if the system is functioning at this time. Usually a knock signal can be generated by tapping on the right exhaust manifold. If no knock signal is generated, try tapping on block close to the area of the sensor.
  3. Because Code 43 sets when the signal voltage on CKT 485 remains low, this test should cause the signal on CKT 485 to go high, The 12 volts signal should be seen by the ECM as "no knock" if the ECM and wiring are OK.
  4. This test will determine if the knock signal is being detected on CKT 496 or if the ESC module is at fault.
  5. If CKT 496 is routed to close to secondary ignition wires, the ESC module may see the interference as a knock signal.
  6. This checks the ground circuit to the module. An open ground will cause the voltage on CKT 485 to be about 12 volts which would cause the Code 43 functional test to fail.
  7. Connecting CKT 496 with a test light to 12 volts should generate a knock signal. This will determine if the ESC module is operating correctly.
Diagnostic Aids :

Code 43 can be caused by a faulty connection at the knock sensor at the ESC module or at the ECM, Also check CKT 485 for possible open or short to ground.

See Diagnosis By Symptoms - No Trouble Codes Stored.

Tim's Auto Repair, mechanic
Category: Chevy
Satisfied Customers: 15313
Experience: Have owned a repair shop for 25 yrs.
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