I got my codes read today and after about 30 minutes of hunting around on Google, I can't seem to find anything except lists of non-OBDII codes. I need some explanations and possible causes for these codes because it's been a while since I actually worked on my truck.

DTC 13 - O2 sensor or circuit
DTC 32 - EGR circuit
DTC 43 - Knock sensor circuit

I got the codes read at O'Reilly, but unfortunately their database in-store only has information about P0XXX codes. If anyone can explain the causes for these codes and possible solutions, I would greatly appreciate it!

 

CODE 13

Trouble Code 13 indicates that the exhaust stream oxygen content sensor (O2 sensor) is not responding as expected. When cold, the sensor is 'biased' by the ECM to about 450 millivolts. Before it warms to at least 600 deg F (315 deg C) it acts as an open circuit and when the ECM reads it, it reads the 450 mV bias. The ECM expects the sensor to warm in a short period of time and begin sending its own voltages.

The conditions for setting this code are:

engine running at least 40 seconds and
no code 21 or 22 (TPS errors) present, and
coolant temperature is at least 118 deg F (48 deg C), and
O2 sensor voltage not fluctuating (i.e. steady between 350 and 557 mV), and
TPS signal indicates above idle (over 6%), and
all the above conditions met for more than 8 seconds

Typical causes for this code include:

1) Defective or degraded O2 sensor
2) Deposit contaminated O2 sensor (running leaded fuel, RTV silicone deposits etc.)
3) Corroded/defective O2 sensor connection
4) Defective sensor ground circuit
5) Defective connection at ECM
6) Defective ECM

CODE 32

Trouble Code 32 indicates that the Exhaust Gas Recirculation (EGR) valve diaphragm is not where the ECM expects it to be. The ECM controls the diaphragm with a Pulse-Width Modulated (PWM) waveform. The EGR has a vacuum bleed solenoid that adjusts the vacuum applied to the EGR valve based on this pulse width. If there is sufficient vacuum at the EGR valve, a switch closes to send a signal back to the ECM. The absence of this signal is the bases for code 32.

The conditions for setting this code are:

no vacuum to EGR (switch open), and
Code 33 or 34 (MAF error) is not present, and
engine running and LV8 is less than 100, and
coolant temperature is > 118 deg F (48 deg C), and
the EGR solenoid duty cycle is < 65%, and
the above conditions are met for more than 25 seconds

Typical causes for this code include:

1) Faulty EGR valve-to-ECM connection
2) Plugged EGR passages and/or sticking EGR valve
3) Defective EGR valve
4) Defective ECM

CODE 43

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. A knock sensor (located at the rear of the engine block) sends signals to an ESC module which then signals the ECM that knocking is being detected. The ECM will retard the timing by as much as 20 degrees in 1 degree increments. A loss of knock sensor signal or loss of ground at the ESC module will cause the signal at the ECM to remain high. The ECM will act as if no knock is present, and may possibly result in engine damage, if there is detonation.

Loss of the ESC signal to the ECM will cause the ECM to constantly retard the timing to its maximum. This results in sluggish performance and a Code 43.
The conditions for setting this code are:

Engine is running
ESC input signal has been low more than 2.23 seconds

Typical causes for this code include:

1) Open or shorted knock sensor
2) Loose knock sensor
3) Excessive mechanical noise within engine
4) Improper or incorrectly installed PROM or CALPACK in the ECM or defective ECM
5) Intermittent open in the EST line to the ignition module