What does the Code 42 on a GM car mean?
Trouble Codes› GM OBD Trouble Codes› GM Code 42 CODE 42 – Electronic Spark Timing or Bypass Fault Trouble Code 42 indicates that there may be a malfunction in the Electronic Spark Timing (EST) system. During cranking, the timing is controlled by the ignition module while the ECM monitors the engine speed.
Why does my engine have trouble code 42?
Trouble Code 42 indicates that there may be a malfunction in the Electronic Spark Timing (EST) system. During cranking, the timing is controlled by the ignition module while the ECM monitors the engine speed. When the engine speed exceeds 400 RPM, the ECM sends a BYPASS signal to the ignition module which switches the timing to ECM control.
What are the causes of a GM code 42 spark fault?
1) BYPASS line is open or grounded 2) EST line is open or grounded 3) PROM or CALPACK not seated properly in the ECM 4) Poor connections between ignition module and ECM 5) Poor routing of EST harness and/or poor quality ignition wires (EMI induced electrical noise) 6) Faulty or incorrect ignition module 7) Faulty ECM Return to Chart
What does the code 43 on a GM spark control mean?
Trouble Codes› GM OBD Trouble Codes› GM Code 43 CODE 43 – Electronic Spark Control Fault Trouble Code 43 indicates that there may be a malfunction in the Electronic Spark Control (ESC)circuit. ESC is used to sense spark knock (pinging) and retard the timing to eliminate it.
What causes a GM engine to set code 42?
When the engine speed exceeds 400 RPM, the ECM sends a BYPASS signal to the ignition module which switches the timing to ECM control. The ECM calculates what the timing should be then “tells” the ignition module via the EST circuit. An open or ground in the EST circuit will stall the engine and set a Code 42.
Where can I Find my GM trouble code?
If you own a 1982 to 1995 GM car or truck, you just might be able to read your trouble codes for free! If you have a connector like this under your dash, read on… (note: this connector may have a black plastic cover over it, so also look for a cover shaped like this, sorry for the messy wires here)
What does trouble code 42 mean on spark timing?
Trouble Code 42 indicates that there may be a malfunction in the Electronic Spark Timing (EST) system.
When does an ECM not set code 42?
Circuit Description. When the system is running on the Ignition Module, that is, no voltage on the by-pass line, the Ignition Module grounds the EST signal. The ECM expects to see no voltage on the EST line during this condition. If it sees a voltage, it sets Code 42 and will not go into the EST mode.
Is the 366 cylinder bore smaller than the gasket?
Tall deck engines are no less likely to incur headgasket failure due to this spacing than a standard engine. In the photo can be seen how much smaller the 366 cylinder bore is than the gasket which sits on it (and yes, this is the first disassembly of a factory engine).
Trouble Codes› GM OBD Trouble Codes› GM Code 42 CODE 42 – Electronic Spark Timing or Bypass Fault Trouble Code 42 indicates that there may be a malfunction in the Electronic Spark Timing (EST) system. During cranking, the timing is controlled by the ignition module while the ECM monitors the engine speed.
Trouble Code 42 indicates that there may be a malfunction in the Electronic Spark Timing (EST) system. During cranking, the timing is controlled by the ignition module while the ECM monitors the engine speed. When the engine speed exceeds 400 RPM, the ECM sends a BYPASS signal to the ignition module which switches the timing to ECM control.
1) BYPASS line is open or grounded 2) EST line is open or grounded 3) PROM or CALPACK not seated properly in the ECM 4) Poor connections between ignition module and ECM 5) Poor routing of EST harness and/or poor quality ignition wires (EMI induced electrical noise) 6) Faulty or incorrect ignition module 7) Faulty ECM Return to Chart
Tall deck engines are no less likely to incur headgasket failure due to this spacing than a standard engine. In the photo can be seen how much smaller the 366 cylinder bore is than the gasket which sits on it (and yes, this is the first disassembly of a factory engine).
What are the conditions for setting code 42?
The conditions for setting code 42 are: System in BYPASS mode but the ignition module is still controlling timing – or – Engine speed > 600 RPM with no EST pulses (ECM controlled timing) going to the ignition module for 200 msec. Typical causes for this code 43 include: 1) BYPASS line is open or grounded 2) EST line is open or grounded
What are the codes for the Check Engine light codes?
34 (1984-86) EGR solenoid circuit shorted or open 34 (1987-1991) speed control shorted or open 35 Cooling fan relay circuit open or shorted 35 (trucks) idle switch motor fault – check connections 36 (turbo) Wastegate control circuit open or shorted 36 (3.9/5.2 RWD) solenoid coil circuit (air switching)