Can someone take a look at the freeze frame to see what is causing P050B ?

[ubergeek]

Freeze Frame DTC: P050B
Fuel System Status: Closed loop, using oxygen sensor feedback to determine fuel mix
Closed loop, using oxygen sensor feedback to determine fuel mix
Calculated engine load value: 39.6078431372549 %
Engine coolant temperature: 51 ℃
Short term fuel % trim - Bank 1: -6.25 %
Long term fuel % trim - Bank 1: -0.78125 %
Short term fuel % trim - Bank 2: -4.6875 %
Long term fuel % trim - Bank 2: 2.34375 %
Engine RPM: 715 rpm
Vehicle speed: 0 km/h
Timing advance: 14 °
Intake air temperature: 16 ℃
MAF air flow rate: 6.43 g/sec
Throttle position: 18 %
Oxygen sensor 2 Bank 1 Voltage: 0.82 V
Oxygen sensor 2 Bank 1 Short term fuel trim: NaN %
Oxygen sensor 2 Bank 2 Voltage: 0.835 V
Oxygen sensor 2 Bank 2 Short term fuel trim: NaN %
Run time since egine start: 00:02:22
Oxygen sensor 1 Wide Range Equivalence ratio: 0
Oxygen sensor 1 Wide Range Voltage: 0 V
Oxygen sensor 5 Wide Range Equivalence ratio: 0
Oxygen sensor 5 Wide Range Voltage: 0 V
Commanded evaporative purge: 0 %
# warm-ups since codes cleared: 0
Distance traveled since codes cleared: 0 km
Barometric pressure: 0 kPa
Oxygen sensor 1 Wide Range Current (mA): 0 mA
Oxygen sensor 1 Wide Range Equivalence ratio: 0
Oxygen sensor 5 Wide Range Current (mA): 0 mA
Oxygen sensor 5 Wide Range Equivalence ratio: 0
Catalyst temperature Bank 1 Sensor 1: 0 ℃
Catalyst temperature Bank 2 Sensor 1: 0 ℃
Catalyst temperature Bank 1 Sensor 2: 0 ℃
Catalyst temperature Bank 2 Sensor 2: 0 ℃

 

[ghs215]

Not enough freeze frame data to analyze...

When monitored P050B code, cold start condition, ambient Air temperature between -7°C and 50°C (19.4°F and 122°F), engine Coolant temperature between -7°C and 50°C (19.4°F and 122°F), the difference between the Ambient Air temperature and ECT temperature at start is equal to or less than 10°C (50°F), engine running at idle only.
Set conditions P050B code, engine speed is 50 rpm or more (depending on vehicle specification) below desired idle speed for at least 3 seconds and the average spark advance is above the threshold, too much spark advance, for a specified time limit.

Default actions:
MIL light will illuminate.

Possible causes P050B code:

Restricted intake air system
Low battery voltage
Fuel contamination
Excessive resistance in the ETC positive circuit
Excessive resistance in the ETC negative circuit
ETC Motor/Throttle Body
Powertrain Control Module (PCM)


Diagnose P050B-Cold start ignition timing performance

Step 1. Check for an active DTC

Turn the ignition on.

Note : Low battery voltage can also cause excessive current draw, in very hot and very cold ambient temperatures. Make sure the battery can pass a load test before continuing.

Start the engine, allow the engine to reach normal operating temperature. With the scan tool, read DTC.

Note : It may be necessary to drive the vehicle to meet the conditions to set this DTC, try to repeat the conditions in which the fault originally set by reviewing the Freeze Frame data.

Is the DTC active or pending ?

Yes, go to step 2.
No, perform the PCM intermittent condition.

Step 2. Throttle plate inspection
Turn the ignition off, remove the air cleaner assembly from the throttle body. Check for any signs of a foreign material (ice, dirty, or excessive carbon build up) on the throttle plate or in the bore causing the throttle plate to stick.

Were any signs of foreign material or scoring of the throttle plate or bore found ?

Yes, remove the debris if possible or replace the throttle body assembly. Disconnect the battery when replacing the Throttle Body Assembly. After installation is complete, use scan tool and select the ETC RELEARN function on the misc function tab scanner.
No, go to step 3.

Step 3. Dirty air filter

Remove and inspect the air filter.

Is the Air Filter dirty ?

Yes, replace the Air Filter.
No ,go to step 4.

Step 4. Contaminated Fuel

Inspect the Fuel for contamination (Dirty, water, or other foreign material).

Is the fuel contaminated ?

Yes, drain the Fuel from the fuel tank into an approved gas holding tank and add clean fuel.
No, go to step 5.

Step 5. Excessive resistance in the ETC positive circuit

Turn the ignition off, disconnect the PCM harness connector.

Caution : Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection.

Using voltmeter perform a voltage drop test. Back probe the ETC Positive circuit at the Throttle Body harness connector and PCM harness connector. Make sure the voltmeter leads are connected so a positive polarity is displayed on the voltmeter.
Start the engine and allow it to reach normal operating temperature. Monitor the voltmeter.

Is the voltage below 0.5 volt ?

Yes, go to step 6.
No, repair the exessive resistance in the ETC positive circuit.

Step 6. Excessive resistance in the ETC Negative circuit

Turn the ignition off, move the voltmeter leads to back probe the ETC Negative circuit at the Throttle Body harness connector and PCM harness connector. Make sure the voltmeter leads are connected so a positive polarity is displayed on the voltmeter. Start the engine and allow it to reach normal operating temperature. Monitor the Voltmeter.

Is the voltage below 0.5 volt ?

Yes, go to step 7.
No, repair the excessive resistance in the ETC Negative circuit.

Step 7. ETC Motor

Turn the ignition off, connect the Throttle Body harness connector. Measure the resistance of the ETC Motor by probing the PCM harness connector for the ETC Positive circuit and the ETC Negative circuit.

Is the resistance between 2.5 and 25 ohms at closed throttle ?

Yes, go to step 8.
No, verify that there is good pin to terminal contact in the throttle body and Powertrain Control Module (PCM) Connectors. Replace the Throttle Body assembly if no problems were found in the connectors. Disconnect the battery when replacing the Throttle Body assembly. After installation is complete, use a

 

[ubergeek]

Wow, super great information. One question is why do I get the actual error 15 min later whereas the freeze frame shows it was triggered only after 00:02:22 of runtime. Is this normal? Is there any chance that an OBDII reader can cause the error actually? I am asking because I've never got this code until I plugged in a BT OBD II and started using it. Perhaps just a random coincident.

 

[ubergeek]

[Solution]

Ok, I'd like to report the solution so that those who have the same problem in the future can address the issue.

I had to use the official Toyota repair manual to troubleshoot the issue as follows.

First of all, P050B trips under the following condition.
P050B
Ignition timing retard value insufficient for 5 seconds or
more during 10 seconds of P050A monitoring duration at
cold start (2 trip detection logic)
• Throttle body assembly
• Mass air flow meter
• Air induction system
• Ventilation hose connections
• VVT system
• ECM

When the engine coolant temperature is between -10°C and 50°C (14°F and 122°F), the ECM calculates
the idling intake air amount for 10 seconds, beginning 3 seconds after the engine starts.
When the accumulated value is below the threshold, the ECM interprets this as a malfunction in the Idle
Speed Control (ISC) system at cold start.
The ECM also monitors the ignition timing at cold start, and judges it to be incorrect when it is advanced to
the same value for a warm engine for 5 seconds or more of the 10 second monitoring period.
Example:
P050A is detected when all conditions below are met.
1. The engine coolant temperature is between -10°C and 50°C (14°F and 122°F) when the engine starts.
2. The engine idles for 13 seconds after engine start.
3. The accumulated intake air amount is below the threshold.
The ECM sets the DTC and illuminates the MIL 3 seconds after the engine is next started (2 trip
detection logic)



As for the steps to troubleshoot:
Add together the SHORT FT #1 and LONG FT #1 values
to obtain the total FUEL TRIM.
If Total of the SHORT FT #1 and LONG FT #1 values
is between -20% and 20%, then you can just go ahead and clean Throttle Body. Here a great video to show how to do this.
In my case, there was pretty bad carbon build-up, and once I cleaned it, everything works fine.

Freeze Frame DTC: P050B
Fuel System Status: Closed loop, using oxygen sensor feedback to determine fuel mix
Closed loop, using oxygen sensor feedback to determine fuel mix
Calculated engine load value: 39.6078431372549 %
Engine coolant temperature: 51 ℃
Short term fuel % trim - Bank 1: -6.25 %
Long term fuel % trim - Bank 1: -0.78125 %
Short term fuel % trim - Bank 2: -4.6875 %
Long term fuel % trim - Bank 2: 2.34375 %
Engine RPM: 715 rpm
Vehicle speed: 0 km/h
Timing advance: 14 °
Intake air temperature: 16 ℃
MAF air flow rate: 6.43 g/sec
Throttle position: 18 %
Oxygen sensor 2 Bank 1 Voltage: 0.82 V
Oxygen sensor 2 Bank 1 Short term fuel trim: NaN %
Oxygen sensor 2 Bank 2 Voltage: 0.835 V
Oxygen sensor 2 Bank 2 Short term fuel trim: NaN %
Run time since egine start: 00:02:22
Oxygen sensor 1 Wide Range Equivalence ratio: 0
Oxygen sensor 1 Wide Range Voltage: 0 V
Oxygen sensor 5 Wide Range Equivalence ratio: 0
Oxygen sensor 5 Wide Range Voltage: 0 V
Commanded evaporative purge: 0 %
# warm-ups since codes cleared: 0
Distance traveled since codes cleared: 0 km
Barometric pressure: 0 kPa
Oxygen sensor 1 Wide Range Current (mA): 0 mA
Oxygen sensor 1 Wide Range Equivalence ratio: 0
Oxygen sensor 5 Wide Range Current (mA): 0 mA
Oxygen sensor 5 Wide Range Equivalence ratio: 0
Catalyst temperature Bank 1 Sensor 1: 0 ℃
Catalyst temperature Bank 2 Sensor 1: 0 ℃
Catalyst temperature Bank 1 Sensor 2: 0 ℃
Catalyst temperature Bank 2 Sensor 2: 0 ℃

 

[ubergeek]

[Final update]

The problem came back after about 20 miles and realized that I didn't reset the ECU. I reset the ECU by disconnecting the battery and I no longer have the problem. After driving 200 miles or so, I was able to successfully complete the emission test.