P0300 and other codes (1 Viewer)

[musthave]

I picked up an LX470 this weekend. Getting some things done on it, first up CEL codes.

P0300 - Random misfire
P0110 Intake Air Temperature Circuit Malfunction
P0100 Mass Air Flow (MAF) Circuit Malfunction
P1320 Igniter

First order of business is the P0300. Surprised to not see a 301 or 302, etc. So, which coil pack to replace? I purchased one but don't have a good idea as to which one to replace. Suggestions?

Then, the other codes and trying to figure out what they likely are.

 

[bigredmachine]

if you have access to techstreem and can see the freeze frame data look at the cylinder misfire count pid and start with the cyl with the highest count. personally I would start with the iat and maf codes as they can cause a misfire and there isn't a specific cylinder that's misfiring so id keep the coil in the bag for now

 

[musthave]

if you have access to techstreem and can see the freeze frame data look at the cylinder misfire count pid and start with the cyl with the highest count. personally I would start with the iat and maf codes as they can cause a misfire and there isn't a specific cylinder that's misfiring so id keep the coil in the bag for now

Got it. So IAT code and MAF code, any good suggestions on those?

 

[bigredmachine]

pull it out and hit it with a little throttle plate or brake cleaner to clean it up, check the connector for any corrosion, look for any chafed wires near the connector, and if you have the fsm test the maf.

if you can see the data list the aif flow should be about 4.7g/sec if the maf is good give or take a little bit. general rule of thumb is flow rate should be close to the engine displacement at idle

 

[musthave]

I don't have the FSM for the 100 yet. I've got the ultragauge and I don't think that will show live data that I am aware. Perhaps time to invest in a better scanner.

 

[bigredmachine]

https://www.amazon.com/Launch-CRP12...id=1516665606&sr=1-14&keywords=obd2+scan+tool

that's what I keep at home for when I'm not at work and its a solid scanner for the price. itll give current and history codes, data list, freeze frame data and can do some active tests. is it as good as a techstream or a high end snap on or matco scan tool, no, but itll get the job dome for checking codes and doing some diag.

if you can see the data thers also a spec for air flow readings for the maf with the engine off, ill see if I can dig that up from one of me class books

 

[bigredmachine]

I wish I took better notes in class but maf should be about .4 g/sec with key on engine off. if you see numbers getting .6 or higher you have a dirty hot wire in the maf as the dirt and debris will insulate the hot wire and cause a poor air flow reading when the engine is running

 

[musthave]

I purchased the scanner, 2 day shipping. That will help me a lot, worthwhile investment.

 

[bigredmachine]

I purchased the scanner, 2 day shipping. That will help me a lot, worthwhile investment.

its a solid scanner for the price and its also updateable so that's a plus as well.

 

[musthave]

Scanner didn't arrive, my overnight shipment won't arrive until Friday. So, I got to work on the MAF, used the 7 step method outlined by @pfran42. Let it idle for 15 minutes, no more MAF code. After resetting codes a few times I still get the 1320 for the igniter. Next up, locate that. Clean?

 

[bigredmachine]

what year is the 470?

 

[bigredmachine]

If DTC P1305 is displayed, check No.2 ignition coil with igniter circuit. If DTC P1310 is displayed, check No.3 ignition coil with igniter circuit. If DTC P1315 is displayed, check No.4 ignition coil with igniter circuit. If DTC P1320 is displayed, check No.5 ignition coil with igniter circuit. If DTC P1325 is displayed, check No.6 ignition coil with igniter circuit. If DTC P1330 is displayed, check No.7 ignition coil with igniter circuit. If DTC P1340 is displayed, check No.8 ignition coil with igniter circuit. If DTCs P1300, P1315, P1325 and P1330 are output simultaneously, IGF1 circuit may be open or short. If DTCs P1305, P1310, P1320 and P1340 are output simultaneously, IGF2 circuit may be open or short. Read freeze frame data using LEXUS hand−held tester or OBD II scan tool. Because freeze frame records the engine conditions when the malfunction is detected. When troubleshooting it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air−fuel ratio was lean or rich, etc. at the time of the malfunction.
1 Check spark plug and spark (See page IG−1).
NG Go to step 4.
OK
2 Check for open and short in harness and connector in IGF and IGT signal circuits between ECM and ignition coil with igniter (See page IN−34).
NG Repair or replace harness or connector.
OK
3 Disconnect ignition coil with igniter connector, and check voltage between terminals IGF1, IGF2 of ECM connector and body ground.
PREPARATION: (a) Remove the glove compartment door. (b) Disconnect the ignition coil with the igniter connector. (c) Turn the ignition switch ON. CHECK: Measure the voltage between terminals IGF1, IGF2 of the ECM connector and body ground. OK: Voltage: 4.5 − 5.5 V
OK Replace ignition coil with igniter.
BE6653 A05305 A05320
ON
IGT1
IGT7
IGT8
IGT6
IGT5
IGT4 IGT2 IGT3
(+) (−)
A03401
IGT Signal Waveform 2 V/ Division
IGT GND IGF GND
20 msec./Division
−DIAGNOSTICS ENGINE
DI−127
324Author: Date:
2001 LEXUS LX470 (RM802U)
NG
Check and replace ECM (See page IN−34).
4 Check for open and short in harness and connector in IGT signal circuit between ECM and ignition coil with igniter (See page IN−34).
NG Repair or replace harness or connector.
OK
5 Check voltage between terminals IGT1 − IGT8 of ECM connector and body ground.
PREPARATION: Remove the glove compartment door. CHECK: Measure the voltage between terminals IGT1 − IGT8 of the ECM connector and body ground when the engine is cranked. OK: Voltage: More than 0.1 V and less than 4.5 V
Reference: INSPECTION USING OSCILLOSCOPE During cranking or idling, check the waveform between terminals IGT1 − IGT8 and E1 of the ECM connector. HINT: The correct waveform appears as shown, with rectangle waves.
NG Check and replace ECM (See page IN−34).
OK
BE6653 A05305 A05320
ON
IGT1
IGT7
IGT8
IGT6
IGT5
IGT4 IGT2 IGT3
(+) (−)
BE6653 A01761 A01861
ON
START
1
(+)( −)
DI−128
−DIAGNOSTICS ENGINE
325Author: Date:
2001 LEXUS LX470 (RM802U)
6 Disconnect ignition coil with igniter connector, and check voltage between terminals IGT1 − IGT8 of ECM connector and body ground.
PREPARATION: (a) Remove the glove compartment door. (b) Disconnect the ignition coil with the igniter connector. CHECK: Measure the voltage between terminals IGT1 − IGT8 of the ECM connector and body ground when the engine is cranked. OK: Voltage: More than 0.1 V and less than 4.5 V
NG Check and replace ECM (See page IN−34).
OK
7 Check ignition coil with igniter power source circuit.
PREPARATION: Disconnect the ignition coil with the igniter connector. CHECK: Measure the voltage between terminal 1 of the ignition coil with the igniter connector and body ground when the ignition switch is turned to ON and START position. OK: Voltage: 9 − 14 V
OK Repair ignition coil with igniter power source circuit.
NG
8 Check for open and short in harness and connector between ignition switch and ignition coil with igniter (See page IN−34).
NG Repair or replace harness or connector.
ok replace coil with ignighter





that's copy and paste from the rm for a 2001, I was just guessing on the year. you said that you all ready have a coil in hand so maybe throw the coil on cyl 5, clear the code and send it bro.

 

[musthave]

what year is the 470?

1999 LX 470

 

[musthave]

If DTC P1305 is displayed, check No.2 ignition coil with igniter circuit. If DTC P1310 is displayed, check No.3 ignition coil with igniter circuit. If DTC P1315 is displayed, check No.4 ignition coil with igniter circuit. If DTC P1320 is displayed, check No.5 ignition coil with igniter circuit. If DTC P1325 is displayed, check No.6 ignition coil with igniter circuit. If DTC P1330 is displayed, check No.7 ignition coil with igniter circuit. If DTC P1340 is displayed, check No.8 ignition coil with igniter circuit. If DTCs P1300, P1315, P1325 and P1330 are output simultaneously, IGF1 circuit may be open or short. If DTCs P1305, P1310, P1320 and P1340 are output simultaneously, IGF2 circuit may be open or short. Read freeze frame data using LEXUS hand−held tester or OBD II scan tool. Because freeze frame records the engine conditions when the malfunction is detected. When troubleshooting it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air−fuel ratio was lean or rich, etc. at the time of the malfunction.
1 Check spark plug and spark (See page IG−1).
NG Go to step 4.
OK
2 Check for open and short in harness and connector in IGF and IGT signal circuits between ECM and ignition coil with igniter (See page IN−34).
NG Repair or replace harness or connector.
OK
3 Disconnect ignition coil with igniter connector, and check voltage between terminals IGF1, IGF2 of ECM connector and body ground.
PREPARATION: (a) Remove the glove compartment door. (b) Disconnect the ignition coil with the igniter connector. (c) Turn the ignition switch ON. CHECK: Measure the voltage between terminals IGF1, IGF2 of the ECM connector and body ground. OK: Voltage: 4.5 − 5.5 V
OK Replace ignition coil with igniter.
BE6653 A05305 A05320
ON
IGT1
IGT7
IGT8
IGT6
IGT5
IGT4 IGT2 IGT3
(+) (−)
A03401
IGT Signal Waveform 2 V/ Division
IGT GND IGF GND
20 msec./Division
−DIAGNOSTICS ENGINE
DI−127
324Author: Date:
2001 LEXUS LX470 (RM802U)
NG
Check and replace ECM (See page IN−34).
4 Check for open and short in harness and connector in IGT signal circuit between ECM and ignition coil with igniter (See page IN−34).
NG Repair or replace harness or connector.
OK
5 Check voltage between terminals IGT1 − IGT8 of ECM connector and body ground.
PREPARATION: Remove the glove compartment door. CHECK: Measure the voltage between terminals IGT1 − IGT8 of the ECM connector and body ground when the engine is cranked. OK: Voltage: More than 0.1 V and less than 4.5 V
Reference: INSPECTION USING OSCILLOSCOPE During cranking or idling, check the waveform between terminals IGT1 − IGT8 and E1 of the ECM connector. HINT: The correct waveform appears as shown, with rectangle waves.
NG Check and replace ECM (See page IN−34).
OK
BE6653 A05305 A05320
ON
IGT1
IGT7
IGT8
IGT6
IGT5
IGT4 IGT2 IGT3
(+) (−)
BE6653 A01761 A01861
ON
START
1
(+)( −)
DI−128
−DIAGNOSTICS ENGINE
325Author: Date:
2001 LEXUS LX470 (RM802U)
6 Disconnect ignition coil with igniter connector, and check voltage between terminals IGT1 − IGT8 of ECM connector and body ground.
PREPARATION: (a) Remove the glove compartment door. (b) Disconnect the ignition coil with the igniter connector. CHECK: Measure the voltage between terminals IGT1 − IGT8 of the ECM connector and body ground when the engine is cranked. OK: Voltage: More than 0.1 V and less than 4.5 V
NG Check and replace ECM (See page IN−34).
OK
7 Check ignition coil with igniter power source circuit.
PREPARATION: Disconnect the ignition coil with the igniter connector. CHECK: Measure the voltage between terminal 1 of the ignition coil with the igniter connector and body ground when the ignition switch is turned to ON and START position. OK: Voltage: 9 − 14 V
OK Repair ignition coil with igniter power source circuit.
NG
8 Check for open and short in harness and connector between ignition switch and ignition coil with igniter (See page IN−34).
NG Repair or replace harness or connector.
ok replace coil with ignighter





that's copy and paste from the rm for a 2001, I was just guessing on the year. you said that you all ready have a coil in hand so maybe throw the coil on cyl 5, clear the code and send it bro.

Wow, that's some detail! I'll get the coil into #5 and see what happens. Wow, thanks for your help!

 

[bigredmachine]

thats straight off of tis, since I guessed on the year if you plan on doing harness checks the pin locations may differ from whats stated above.

also after step 5 it states replace the ecu after that step, don't bother with replacing the ecu. I have no idea what the logic is with Toyota but they usually have replace the computer as an early repair instead of more as a last component to be replaced. for what its worth in the last 10 years, besides water ddamage, ive seen 2 computers go bad due to internal failure so failure rate of the computer is pretty low

 

[musthave]

Replaced all plugs. Installed new coil pack on #5, no more CEL codes, that cleared everything. Got the CRP123 scanner finally but I guess I got one that isn't supported by USA support team, I was not able to update it and they recommended returning it. So, I need to find another code scanner that has realtime data.

 

[Les Summer]

I have a 2000 Land Cruiser and I'm getting P1300 P1325 and P1330 simultaneously. I recently did my 30k routine check of my spark plugs to make sure they were not loose. My plugs now have 30k on them since new, and are NGK I purchased from the dealer. I swapped coils around just for good measure, and I repeatedly get the same codes. I have a FSM, and it states like you said, signs point to an open short in the IGF1 circuit, and I'm not sure how I'm going to test that, or what I'm going to replace. I purchased a single pigtail from advanced auto, just in case I'm lucky and only need to snip a plug and a short amount of wire to eliminate the open circuit. I guess I'm planning to start pulling wire harnesses apart until I find the open short. I am pretty sure that's what it's going to be, since I had ZERO issues until I started unplugging and moving the wire harness around. I wish I could just replace a small part of the harness, plug and play, without having to test continuity in wires. it's going to be a project.

 

[Les Summer]

So I dug deeper into the field service manual, and it actually suggests to unplug and re-plug the ignition coils as the problem is more likely to be with the plug itself than actual wires, so I took advice and lo and behold 50 miles of driving and no check engine light, but I will keep monitoring the situation…