1992 Chevy Caprice Car boggs down, code 43

Tiny
FREDALBOB
  • MEMBER
  • 1992 CHEVROLET CAPRICE
  • V8
  • 2WD
  • AUTOMATIC
  • 192,000 MILES
Code 43
Car will become sluggish with no power even with pedal all the way down. If you restart the key, the car will run fine for a bit. But the car still boggs out. Car runs fine sometimes then suddenly back to the bogg. Also at hard excelleration or stomp down take off their stumble and check engine light comes on with code 43.
Replaced Fuel pump
computer and computer chip
knock sensor
ECM
Fuel Filter
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Saturday, September 18th, 2010 AT 8:34 PM

6 Replies

Tiny
RASMATAZ
  • MEMBER
DTC 43 Electronic Spark Control (ESC) Circuit

CODE 43, ESC ERROR, W/ESC MODULE
NOTE:Test numbers refer to numbers on diagnostic chart.

If conditions for a Code 43 exist, "Scan" tester will indicate knock signal presence. Knock signal should not exist at idle unless an internal or system problem exists.
Determines if system is currently functioning. Usually, a knock signal can be generated by tapping on exhaust manifold. If knock signal is not generated, try tapping on engine block closer to sensor.
Because Code 43 sets when signal voltage on spark retard line remains low, this test should cause signal on that line to go high. Control module should see 12-volt signal as a "no knock" signal if control module and wiring are okay.
This test will determine if knock signal is being detected on sensor-to-controller line or if ESC module is at fault.
If sensor line is routed too close to secondary ignition wires, ESC module may see induced interference as a knock signal.
This checks ground circuit to module. An open ground will cause voltage on monitored line to constantly remain about 12 volts. This would cause Code 43 functional test to fail.
Contacting sensor-to-controller wire using a test light connected to 12 volts will generate a knock signal to controller. This will determine if ESC controller is operating correctly.
Diagnostic Aids
Code 43 can be caused by a faulty connection at knock sensor, ESC module or control module. Check controller-to-control module signal line for an open or short to ground. Check for poor connections and damaged harness. Inspect control module harness connectors for backed-out sensor signal and ECM input signal terminals, improper mating, broken locks, improperly formed or damaged terminals and damaged harness. If connections and harness are okay, monitor knock signal parameter using "Scan" tester while moving related connectors and wiring harness. If failure is induced, knock signal will abruptly change. This may help to isolate malfunction.
Fig. 38: Code 43

Fig. 39: Code 43, Schematic, "D" Body, W/ESC Module, ESC Error
Fig. 40: Code 43, Flow Chart, ESC Error, W/ESC Module
CODE 43, ESC ERROR, W/O ESC MODULE
NOTE:Test numbers refer to numbers on diagnostic chart. If an audible knock is heard from engine at idle, repair internal engine problems before proceeding.

If tapping on engine does not produce a knock signal on "Scan" tester, try tapping engine closer to sensor before proceeding.
ECM supplies a 5-volt reference signal on knock sensor line. With knock sensor connected, this signal is pulled low to about 2.5 volts. Knock signal, which is an AC signal, rides on this 2.5-volt DC signal.
This test determines if knock sensor is faulty or if ESC portion of MEM-CAL is faulty.
Diagnostic Aids
Check knock sensor signal circuit for a potential open or short to ground. An open knock signal circuit would cause 5-volt reference to remain high at ECM knock signal terminal. A short to ground in knock signal circuit would cause 5-volt reference signal to pull low to near zero volts. Resistance to ground through knock sensor should be 3300-4500 ohms. Also check for proper installation of MEM-CAL
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Sunday, September 19th, 2010 AT 4:47 AM
Tiny
FREDALBOB
  • MEMBER
What do you mine by sensor-to-controller line?
Where can I find these figures?
There is a rattling coming from my motor, could this potentially set off a knock sensor code?
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Sunday, September 19th, 2010 AT 2:18 PM
Tiny
RASMATAZ
  • MEMBER
If your engine is pinging/detonating rather then an engine knocking noises. It'll set DTC 43 if its not retarding the ignition timing-also might wanna check the EGR valve, this one can cause the engine to detonate if its not recirculating the exhaust gases
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Sunday, September 19th, 2010 AT 5:31 PM
Tiny
FREDALBOB
  • MEMBER
Ok I just replaced the radiator in the car, but it still heats majorly after setting off the code. Also the oil pressure will have a sudden drop.

Could the heat possibly be caused by a blown head gasket?
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Saturday, September 25th, 2010 AT 12:12 AM
Tiny
RASMATAZ
  • MEMBER
To rule out the headgasket you have to block and pressure test it-
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Saturday, September 25th, 2010 AT 1:02 AM
Tiny
FREDALBOB
  • MEMBER
What can I do by myself to rule out some things?
Or maybe some other solutions?
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Saturday, September 25th, 2010 AT 1:06 PM

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